What is absorbent opal? Absorbent opal is a hydrophilic variety of opal mineral characterized by its unique ability to absorb and retain water, containing up to 20% water by weight within its amorphous silica structure. This mineraloid, discovered in volcanic deposits, exhibits a distinctive porous network of microscopic channels that facilitate fluid absorption and retention. […]
What is agate opal ? Agate opal is a rare mineralogical phenomenon where opal forms within the banded structure of agate, creating a unique composite gemstone that exhibits both the translucent layering of agate and the play-of-color characteristic of precious opal. The stone forms when silica-rich solutions infiltrate cavities in volcanic rocks, depositing layers of […]
What is amber opal? Amber opal is a rare variety of opal that exhibits a distinctive honey-yellow to golden-brown body color, combining the organic nature of amber with the play-of-color characteristic of precious opal. This gemstone forms through the silicification of ancient tree resin, where silica-rich solutions infiltrate the amber’s molecular structure. The stone’s unique […]
What is Andamooka opal? Andamooka opal is a distinctive form of matrix opal found exclusively in Andamooka, South Australia, characterized by its unique crystal structure and potch opal composition within a limestone host rock. The opal exhibits a natural dark body tone and displays vibrant play-of-color through its silica spheres when treated with a sugar-acid […]
What is banded opal? Banded opal is a distinctive variety of common opal exhibiting parallel bands of varying colors arranged in horizontal layers, formed through sequential deposition of silica-rich solutions in fissures or cavities within host rocks. This mineraloid, composed of hydrated silica (SiO2¬∑nH2O), displays no play of color like precious opal but presents striking […]
What is Bandfire opal? Bandfire opal is a premium variety of precious opal distinguished by sequential bands of spectral color that create a rolling fire effect across its surface. The gem forms in the sedimentary deposits of Lightning Ridge, New South Wales, through a process of silica-rich solution solidification under specific geological conditions. The stone’s […]
What is belemnite opal? Belemnite opal is a rare fossilized form of opal that occurs when silica-rich solutions replace the calcite guards of extinct cephalopod mollusks known as belemnites during the mineralization process. The resulting gemstone maintains the distinctive bullet-shaped structure of the original belemnite fossil while displaying the characteristic play-of-color typical of precious opal. […]
What is black opal body tone? Black opal body tone is the fundamental darkness level or background color inherent in precious opal, ranging from N1 (darkest) to N9 (lightest) on the standardized GIA grading scale. This intrinsic darkness determines the contrast and visibility of the opal’s play-of-color against its base. Dark body tones (N1-N4) create […]
What is blue opal? Blue opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) characterized by its distinctive blue coloration, caused by light diffraction through its microstructure of silica spheres. This precious gemstone belongs to the opal family, displaying varying degrees of opalescence and play-of-color phenomena. The mineral forms in volcanic rocks’ cavities through low-temperature […]
What is bone opal? Bone opal is a rare fossilized material formed when ancient animal bones undergo mineralization, where the original organic matter is replaced by opal through silicification processes. This unique gemstone preserves the microscopic structure of the original bone tissue while displaying the characteristic play-of-color associated with precious opal. The formation occurs in […]
What is cachalong opal? Cachalong opal is a rare, porcelain-white to cream-colored variety of common opal (SiO2¬∑nH2O) characterized by its opaque appearance and waxy luster. This mineraloid, also known as pearl opal or mother-of-pearl opal, forms through low-temperature hydrothermal processes in volcanic rocks. The mineral exhibits distinctive physical properties, including a Mohs hardness of 5.5-6.0, […]
What is ceraunium opal? Ceraunium opal is a rare variety of natural opal characterized by its distinctive thunderbolt patterns and electrical discharge markings, historically associated with fulgurites and believed to be formed by lightning strikes. The stone exhibits unique dendritic inclusions that create intricate branching patterns resembling lightning bolts frozen within the opal’s structure. The […]
What is cherry opal? Cherry opal is a rare variety of common opal exhibiting a distinctive deep red to burgundy color caused by iron oxide inclusions within its amorphous silica structure. This gemstone, discovered in Mexico’s Magdalena region, displays a characteristic vitreous to resinous luster with a hardness of 5.5-6.5 on the Mohs scale. The […]
What are chinese writing opals? Chinese writing opals is a rare variety of precious opal exhibiting natural patterns that resemble Chinese calligraphic characters or script-like formations within its internal structure. These distinctive opals, found primarily in Australia’s Lightning Ridge region, display black, dark blue, or gray base colors with vivid play-of-color effects that form character-like […]
What is chloropal? Chloropal is a rare variety of common opal characterized by its distinctive bright green coloration, caused by the presence of copper and nickel minerals within its amorphous silica structure. This mineraloid, discovered in 1969 in Western Australia, exhibits a unique combination of cryptocrystalline silica and varying amounts of water content, typically ranging […]
What is chrysopal opal? Chrysopal is a rare variety of opal characterized by its distinctive apple-green to bluish-green coloration, caused by the presence of nickel silicate within its amorphous silica structure. The gemstone exhibits a unique play of color, displaying flashes of green and gold when viewed from different angles. Found predominantly in Australia’s Queensland […]
What is claro opal? Claro opal is a transparent to translucent variety of precious opal displaying vivid play-of-color against a clear or colorless background, predominantly found in Mexico’s Queretaro deposits. The stone exhibits a unique optical phenomenon called opalescence, created by the regular arrangement of silica microspheres that diffract light. The Mexican claro opal forms […]
What is common opal? Common opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) characterized by its non-iridescent, translucent to opaque appearance and variable coloration ranging from white to red, yellow, blue, or green. The mineral forms through low-temperature hydrothermal processes where silica-rich solutions deposit in rock cavities, fractures, and sedimentary layers. This mineraloid exhibits […]
What is contra luz opal? Contra luz opal is a rare hydrated silica variety that exhibits a unique optical phenomenon where light passes through the transparent to translucent body of the opal, creating distinctive play-of-color patterns visible from both sides. The name derives from Spanish “”contra luz,”” meaning “”against the light,”” referring to its primary […]
What is Coober Pedy opal? Coober Pedy opal is a precious gemstone mined in the South Australian desert town of Coober Pedy, characterized by its distinctive play-of-color and high silica content. The opal forms in the geological white claystone bands of the Great Artesian Basin, deposited during the Cretaceous period approximately 150 million years ago. […]
What is dark opal? Dark opal is a rare form of precious opal exhibiting a dark body tone, predominantly black, gray, or blue, against which vibrant play-of-color displays in spectral hues. This gemological phenomenon occurs in silica deposits where spheres of amorphous silicon dioxide create a three-dimensional diffraction grating. The most valuable dark opals originate […]
What is dendritic opal? Dendritic opal is a form of common opal containing tree-like or branching inclusions of manganese or iron oxides, creating distinctive patterns reminiscent of organic plant growth. The mineral belongs to the opal-A group with a chemical composition of SiO2¬∑nH2O, displaying no play-of-color characteristic. The dendrites form through mineral infiltration during the […]
What is Ethiopian opal? Ethiopian opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) discovered in 2008 near Wegel Tena, Ethiopia, distinguished by its unique hydrophane properties and remarkable play-of-color characteristics. This precious gemstone forms in volcanic deposits through the precipitation of silica-rich solutions within vesicles and fractures of the host rock. The stone exhibits […]
What is fire opal? Fire opal is a translucent to transparent variety of opal displaying warm body colors of yellow, orange, or red, caused by traces of iron oxide within its chemical structure of hydrated silica (SiO2¬∑nH2O). The gem occurs primarily in volcanic regions, formed when silica-rich water fills cavities in rhyolite and other igneous […]
What is flame opal? Flame opal is a rare variety of precious opal characterized by its distinctive play-of-color featuring dominant red, orange, and yellow hues that create a flickering flame-like appearance within the gemstone’s transparent to translucent body. The gem forms in volcanic regions when silica-rich solutions infiltrate rock cavities, depositing hydrated silica spheres in […]
What is flash opal? Flash opal is a rare variety of precious opal characterized by a distinctive optical phenomenon where vibrant colors flash directionally across the stone’s surface when viewed from specific angles. The phenomenon occurs due to the diffraction of light through uniformly-sized silica spheres arranged in a regular pattern within the opal’s microstructure. […]
What is flashfire opal? Flashfire opal is a rare variety of precious opal exhibiting intense, dynamic play-of-color with dominant red-to-orange flashes that appear to move rapidly across the stone’s surface when viewed from different angles. The phenomenon occurs due to the unique internal structure of uniformly arranged silica spheres that diffract light. This distinctive gem […]
What is Fossil Opal? Fossil opal is a mineraloid formed when silica-rich solutions infiltrate and replace organic materials in fossils, creating a unique form of preservation where the original structure is maintained through opalescence. The process, known as opalization, occurs when hydrated silica gel fills microscopic voids in buried organic matter, resulting in a three-dimensional […]
What is Freeform Opal? Freeform opal is a naturally occurring hydrated amorphous form of silica, shaped through non-traditional cutting techniques that follow the stone’s natural contours rather than conventional faceting patterns. This distinctive gemstone exhibits play-of-color through a phenomenon called diffraction, where light interacts with microscopic silica spheres arranged in a regular pattern. The cutting […]
What is gold opal? Gold opal is a precious gemstone variety characterized by a dominant yellow to golden background color with vibrant play-of-color flash patterns across its surface. The stone forms when silica spheres arrange in a regular pattern within hydrated silica dioxide, creating a three-dimensional diffraction grating that splits white light into spectral colors. […]
What is Harlequin opal? Harlequin opal is a rare and distinctive variety of precious opal characterized by its mosaic-like pattern of angular, regularly-shaped color patches resembling a checkerboard or diamond arrangement. These geometric color segments display sharp, well-defined boundaries and exhibit intense play-of-color across the visible spectrum. The formation occurs in volcanic host rocks where […]
What is honey opal? Honey opal is a rare variety of precious opal displaying a dominant yellow to golden-amber body tone with distinctive play-of-color phenomena. This gemstone forms through the deposition of silica spheres in sedimentary or volcanic rocks under specific geological conditions. The distinctive honey-colored base is caused by trace amounts of iron oxide […]
What is hungarian opal? Hungarian opal is a precious hydrated amorphous form of silica (SiO2¬∑nH2O) found exclusively in the ancient volcanic regions near V√∂r√∂sv√°g√°s, Hungary. This gemstone exhibits a distinctive play-of-color phenomenon through diffraction of light across regularly arranged microscopic silica spheres within its internal structure. The stone formed during the Miocene epoch through hydrothermal […]
What is hyacinth opal? Hyacinth opal is a rare variety of fire opal exhibiting a distinctive reddish-orange to deep red color reminiscent of the hyacinth flower, composed of hydrated silica with microscopic spheres that create its unique play of color. The gemstone forms in volcanic regions where silica-rich solutions penetrate rock cavities, crystallizing under specific […]
What is jasper opal? Jasper opal is a naturally occurring silica-based gemstone that combines the structural characteristics of both jasper and opal, exhibiting a unique matrix where common opal forms within jasper host rock. The stone displays distinctive patterns of opalization within its jasper framework, creating a remarkable interplay between the opaque qualities of jasper […]
What is jelly opal? Jelly opal is a translucent to semi-transparent variety of hydrated silica (SiO2¬∑nH2O) characterized by its distinctive gelatinous appearance and lower specific gravity compared to other opal varieties. The gemstone exhibits a unique internal structure of closely packed silica spheres with interstitial water content ranging from 6-10% by weight. This rare form […]
What is lechosos opal? Lechosos opal is a rare variety of white opal characterized by its milky, translucent appearance and distinct play-of-color phenomenon, predominantly found in the Andes Mountains of Peru at elevations exceeding 4,000 meters. The gemstone exhibits a unique combination of opalescence and chatoyancy, displaying vibrant flashes of blue, green, and occasionally red […]
What is lemon opal? Lemon opal is a rare variety of precious opal displaying a distinctive yellow to golden-yellow body tone, characterized by its play-of-color phenomenon within the visible spectrum of 400-700 nanometers. This silica-based mineraloid contains 6-10% water content and forms through the deposition of silica gel in rock cavities. The gemstone exhibits potch […]
What is leopard opal? Leopard opal is a rare variety of dendritic opal characterized by distinctive spotted patterns resembling leopard spots, formed through the presence of manganese or iron oxide inclusions within the silica matrix. This gemstone occurs primarily in Mexico, particularly in the Magdalena region, where specific geological conditions create its unique appearance. The […]
What is levin opal? Levin opal is a rare hydrophane opal variety discovered in Levin, New Zealand, characterized by its unique ability to become transparent when immersed in water and return to opacity when dry. The stone exhibits a distinctive play-of-color, displaying predominantly blue and green flashes across its surface, with occasional red and orange […]
What is light crystal opal? Light crystal opal is a transparent to translucent variety of precious opal displaying vibrant play-of-color against a clear to white base, characterized by its high clarity and distinct spectral flash patterns. The gemstone exhibits a unique internal structure of uniformly-sized silica spheres arranged in a regular grid-like pattern, creating diffraction […]
What is light opal? Light opal is a translucent to semi-transparent variety of opal characterized by its pale, pastel background color and subtle play-of-color effect displaying predominantly white, yellow, and blue spectral hues. This gemstone exhibits a lower specific gravity ranging from 1.98 to 2.20 due to its higher water content compared to other opal […]
What is lightning ridge opal? Lightning Ridge Opal is a rare and precious gemstone variety of hydrated silica, distinguished by its unique dark body tone and vibrant play-of-color, found exclusively in Lightning Ridge, New South Wales, Australia. This specific opal type forms in the weathered sedimentary rocks of the Griman Creek Formation, deposited during the […]
What is lithoxyl opal? Lithoxyl opal is a rare form of petrified wood where the original organic material has been completely replaced by opal, preserving the cellular structure of the ancient wood in remarkable detail. The mineralization process occurs when silica-rich solutions infiltrate and replace the wood’s organic matter while maintaining its microscopic anatomy. This […]
What is liver opal? Liver opal is a rare variety of common opal exhibiting a distinctive reddish-brown to deep mahogany color, closely resembling the appearance of raw liver tissue. The unique coloration stems from high concentrations of iron oxide inclusions within its amorphous silica structure. This specialized form of opal occurs primarily in volcanic regions, […]
What is Mexican fire opal? Mexican fire opal is a transparent to translucent variety of opal (SiO2¬∑nH2O) characterized by its intense red, orange, and yellow play-of-color, formed through hydrothermal processes in the rhyolitic lava fields of Mexico. This rare gemstone contains between 3-10% water content within its amorphous silica structure, distinguishing it from common opal […]
What is milk opal? Milk opal is a rare variety of common opal characterized by its opaque white body color and distinct milky appearance, composed primarily of hydrated silica (SiO2¬∑nH2O) with microscopic spheres of amorphous silica creating its distinctive optical properties. This cryptocrystalline form occurs in volcanic regions where silica-rich solutions penetrate host rocks, typically […]
What is milky opal? Milky opal is a variety of common opal characterized by its translucent to opaque appearance with a distinct white or bluish-white body color, lacking the play-of-color found in precious opal. The stone’s milky appearance results from microscopic silica spheres arranged in an irregular pattern, causing light to scatter diffusely through the […]
What is monarch opal? Monarch opal is a rare variety of precious opal exhibiting a distinctive pattern of orange and black colors, predominantly found in the Virgin Valley of northern Nevada, United States. This gemstone displays a unique play-of-color phenomenon characterized by bright orange flashes against a dark background matrix, reminiscent of the coloration seen […]
What is moss opal? Moss opal is a translucent to semi-transparent variety of common opal characterized by green, brown, or black dendritic inclusions that create patterns resembling moss, ferns, or algae. These inclusions consist primarily of manganese or iron oxide minerals that formed during the opal’s crystallization process. The stone forms in volcanic regions where […]
What is mother of opal? Mother of opal is a naturally occurring form of non-crystalline hydrated silica, distinguished from precious opal by its lack of play-of-color and characterized by its opaque, porcelain-like appearance. The material forms in sedimentary deposits through the precipitation of silica from groundwater, typically appearing in white, cream, or pale blue-gray hues. […]
What is mountain opal? Mountain opal is a rare variety of common opal found in volcanic mountainous regions, characterized by its translucent to opaque appearance and distinctive play of colors within a predominantly white or cream-colored matrix. This silica-based mineraloid forms in volcanic host rocks through the precipitation of silica-rich solutions in cavities and fissures […]
What is Nevada opal? Nevada opal is a precious mineraloid composed of hydrated silica (SiO2¬∑nH2O) found exclusively in the Virgin Valley of northern Humboldt County, Nevada. This rare gemstone exhibits remarkable play-of-color, displaying vibrant spectral hues through its characteristic diffraction of light through a regular arrangement of silica spheres. The formation occurred during the Miocene […]
What is non precious opal? Non precious opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) lacking the iridescent play-of-color characteristic found in precious opal. The mineral forms in sedimentary rocks through the precipitation of silica from low-temperature solutions, typically containing 6-10% water content by weight. Common opal occurs in various colors including white, yellow, […]
What is onyx opal? Onyx opal is a rare variety of common opal exhibiting a black base color with play-of-color flashes, formed through the natural deposition of silica spheres within volcanic rock matrices. The gemstone displays distinctive optical phenomena characterized by iridescent flashes of spectral colors against its dark background. The formation process occurs when […]
What is opal matrix? Opal matrix is a naturally occurring host rock formation that contains precious opal deposits within its structural cavities and fissures. The matrix consists primarily of sedimentary or volcanic materials, most commonly sandstone, claystone, or ironstone, which serve as the foundational structure where opal forms through silica-rich water deposition. Australian opal fields, […]
What is opalized bone? Opalized bone is a form of fossilized remains where the original organic material has been replaced by opal through a mineralization process known as permineralization. The process occurs when silica-rich water infiltrates bone tissue, gradually replacing the organic matter while maintaining the original bone structure at a microscopic level. These rare […]
What is opalized fossil? Opalized fossil is a unique form of fossilization where organic material has been replaced by opal, a hydrated amorphous silica mineral. The process occurs when silica-rich water permeates organic remains, gradually replacing the original tissue with opal while maintaining the specimen’s detailed morphological structure. Australian opalized fossils represent the world’s finest […]
What is opalized shell? Opalized shell is a rare fossilized formation where ancient mollusk shells have been replaced by precious opal through a mineralization process spanning millions of years. The original calcium carbonate structure of the shell transforms into hydrated silica gel, preserving the shell’s intricate patterns while displaying the characteristic play-of-color found in precious […]
What is opalized wood? Opalized wood is a rare form of petrified wood where the original organic material has been replaced by opal (hydrated silica) through a mineralization process spanning millions of years. The transformation occurs when silica-rich water infiltrates buried wood, preserving the cellular structure while converting it into precious opal. This fossilized material […]
What is pearl opal? Pearl opal is a rare variety of opal exhibiting a distinctive pearlescent sheen combined with the characteristic play-of-color found in precious opals. This hydrated amorphous form of silica contains between 6-10% water content and displays a unique structural composition of microscopic silica spheres arranged in a regular pattern. The gemstone manifests […]
What is peruvian opal? Peruvian opal is a mineraloid hydrated silica (SiO2¬∑nH2O) formed in the Andes Mountains of Peru, distinguished by its semi-opaque to translucent blue-green coloration and unique dendrite inclusions. This volcanic-originated gemstone exhibits a hardness of 5.5-6.5 on the Mohs scale and possesses a vitreous to resinous luster. The stone forms in volcanic […]
What is pineapple opal? Pineapple opal is a rare variety of common opal exhibiting distinctive yellow-gold to amber coloration with a unique internal structure resembling the geometric pattern of a pineapple’s skin. This silica-based mineraloid, discovered primarily in Mexico’s state of Jalisco, forms through the precipitation of silica-rich solutions in volcanic host rocks. The distinctive […]
What is pinfire opal? Pinfire opal is a rare variety of precious opal exhibiting distinct pinpoint flashes of spectral colors against a transparent to translucent base. The phenomenon occurs when small, concentrated areas of color play create distinct points of fire throughout the gemstone’s structure. The unique optical effect in pinfire opals results from the […]
What is pinpoint opal? Pinpoint opal is a rare variety of precious opal characterized by minute points of spectral color flash against a dark or light background matrix. The phenomenon occurs when uniform, microscopic spheres of silica create a three-dimensional diffraction grating that produces distinct pinpoints of spectral color play. These opals form in volcanic […]
What is pipe opal? “Pipe opal is a rare form of precious opal found exclusively in Lightning Ridge, New South Wales, Australia, characterized by its distinctive cylindrical or tubular formation within ironstone concretions. The opal forms in vertical pipe-like structures through ancient plant root channels, where silica-rich solutions deposited opal during the Cretaceous period. These […]
What is pitch opal? Pitch opal is a rare variety of common opal characterized by its opaque black body color and complete absence of play-of-color, formed through the natural inclusion of carbonaceous materials within its amorphous silica structure. This distinctive gemstone occurs primarily in Lightning Ridge, New South Wales, Australia, where it forms in ancient […]
What is potch opal? Potch opal is a common variety of non-precious opal lacking the characteristic play-of-color found in precious opal, consisting primarily of amorphous hydrated silica spheres arranged in a non-diffractive pattern. The mineraloid occurs in various colors from white to gray, brown, or black, displaying no spectral phenomena due to its internal structure’s […]
What is prase opal? Prase opal is a rare variety of common opal displaying a distinctive leek-green to apple-green coloration, caused by microscopic inclusions of nickel-rich chlorite minerals within its amorphous silica structure. This cryptocrystalline form of hydrated silicon dioxide exhibits a characteristic internal play of color distinct from precious opal, presenting a uniform translucent […]
What is precious fire? Precious fire opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) distinguished by its internal play of iridescent colors against a translucent to transparent body color, typically ranging from water-clear to milky white. The phenomenon, known as opalescence, occurs through the diffraction of light within a precise arrangement of silica microspheres. […]
What is precious opal? Precious opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) displaying play-of-color, a unique optical phenomenon caused by the diffraction of light through a regular array of silica microspheres. These microspheres, ranging from 150 to 300 nanometers in diameter, create a three-dimensional structure that breaks white light into spectral colors. The […]
What is Queensland opal? Queensland opal is a precious gemstone formed from hydrated silica deposits found predominantly in Australia’s Great Artesian Basin, characterized by its distinctive play-of-color and exceptional brightness across the visible spectrum. The stone exhibits a unique internal structure of uniformly-sized silica spheres arranged in a regular grid pattern, creating diffraction gratings that […]
What is quinzite opal? Quinzite opal is a non-existent gemstone variety. The term appears to be a fabrication or misconception, as it does not occur in mineralogical literature, scientific databases, or gemological records. Common opal varieties include precious opal, fire opal, boulder opal, and common opal, each defined by their distinct optical and physical properties. […]
What is radiolite opal? Radiolite opal is a rare variety of opal formed through the silicification of ancient marine organisms called radiolarians, creating a distinctive fossil-bearing precious gemstone with microscopic skeletal remains preserved in opaline silica. The stone exhibits a unique internal structure where the calcium carbonate shells of prehistoric radiolarians have been replaced by […]
What is rainbow opal? Rainbow opal is a rare form of precious opal exhibiting a full spectral display of iridescent colors through its internal structure of uniformly-sized silica spheres. This hydrated amorphous form of silica (SiO2¬∑nH2O) diffracts white light into its spectral components through a three-dimensional array of microspheres. The stone’s distinctive play-of-color occurs through […]
What is red flash opal? Red flash opal is a rare variety of precious opal exhibiting a distinct red-orange flash or play-of-color phenomenon when viewed from specific angles under direct light. This phenomenal gemstone belongs to the mineraloid class of hydrated amorphous silica (SiO2¬∑nH2O), featuring a unique internal structure of uniformly sized silica spheres arranged […]
What is seam opal? Seam opal is a distinct variety of precious opal found in horizontal or vertical fissures within host rock matrices, characterized by its formation in thin layers or veins. These opals exhibit play-of-color through a natural phenomenon called diffraction, where light interacts with microscopic silica spheres arranged in a regular pattern. Australian […]
What is a semi black opal? Semi black opal is a rare variety of opal exhibiting play-of-color against a dark gray to semi-black body tone, composed of hydrated silica dioxide with 6-10% water content, formed in sedimentary rocks under specific geological conditions. The gemstone displays a distinctive color play caused by the diffraction of light […]
What is semiopal? Semiopal is a variety of common opal characterized by its translucent to opaque appearance and incomplete play of color, displaying partial iridescence across its surface. The mineral belongs to the silicate class, composed primarily of hydrated silica (SiO2¬∑nH2O) with varying amounts of water content. The stone forms through the deposition of silica-rich […]
What is shell opal? Shell opal is a naturally occurring form of opal that develops within the cavities of fossilized mollusks, particularly those from the Cretaceous period, exhibiting play-of-color within ancient shell matrices. This rare variety forms when silica-rich solutions infiltrate and replace the original calcium carbonate structure of marine shells, creating a unique combination […]
What is sun opal? Sun opal is a rare variety of precious opal exhibiting distinct play-of-color characteristics when exposed to direct sunlight, displaying vibrant spectral hues through its internal structure of uniformly arranged silica spheres. This phenomenal gemstone, composed of hydrated silica (SiO2¬∑nH2O), belongs to the opal group of minerals and forms in sedimentary deposits. […]
What is water opal? Water opal is a transparent to translucent variety of hydrophane opal that exhibits remarkable optical properties when immersed in water, displaying enhanced play-of-color and transparency due to its porous microstructure. The stone, composed of amorphous silica dioxide with varying percentages of water content, belongs to the mineraloid class of gemstones. This […]
What is wax opal? Wax opal is a distinctive variety of common opal exhibiting a waxy luster and translucent to opaque appearance, characterized by its resinous sheen and microscopic spherical silica structure. The mineral forms through low-temperature hydrothermal processes, where silica-rich solutions deposit within rock cavities under specific geological conditions. This mineraloid contains 6-10% water […]
What is welo opal? Welo opal is a precious hydrated silica gemstone exclusively mined from the Welo province in northern Ethiopia, characterized by its distinctive play-of-color and transparent to translucent body tone. The stone formed during the Oligocene to Miocene epochs within volcanic host rocks through the deposition of silica-rich solutions in cavities and fissures. […]
What is White Cliffs? White Cliffs opal is a distinctive form of precious opal mined exclusively in White Cliffs, New South Wales, Australia, characterized by its unique seam structure and high silica content formed within Early Cretaceous sedimentary deposits. The opal exhibits exceptional play-of-color, displaying vibrant spectral hues against a predominantly white to light gray […]
What is white opal? White Opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) characterized by its milky-white to translucent appearance and distinctive play of colors known as opalescence. This precious gemstone exhibits a unique internal structure of uniformly sized silica spheres arranged in a regular pattern, creating diffraction of light that produces its characteristic […]
What is white opal? White opal is a hydrated amorphous form of silica (SiO2¬∑nH2O) characterized by its distinctive white body color and iridescent play-of-color, displaying spectral hues through a phenomenon called diffraction. The gemstone forms in sedimentary rocks when silica-rich water fills cracks and cavities, creating a precise arrangement of microscopic silica spheres. The unique […]
