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 deposits and limited locations in Tanzania, chrysopal forms through the precipitation of silica-rich solutions in rock cavities under specific geological conditions. The stone’s internal structure consists of uniformly sized spheres of silica arranged in a regular pattern, creating its characteristic opalescence. Its hardness ranges from 5.5 to 6.5 on the Mohs scale, with a specific gravity of 2.0 to 2.2. The gem’s refractive index typically measures between 1.44 and 1.46, distinguishing it from other green gemstones.
Chrysopal opal is typically a natural gemstone.
Common names for Chrysopal opal include lemon opal, green opal, and prase opal.
Chrysopal, a variety of common opal, generally has a hardness of around 5.5 to 6.5 on the Mohs scale. This makes it relatively softer than many other gemstones and somewhat susceptible to scratches and abrasion.
The refractive index of Chrysopal typically ranges from 1.44 to 1.46, which is relatively low compared to other gemstones. This contributes to its subtle luster.
Chrysopal exhibits a waxy to dull luster, typical of opal varieties. This luster gives it a soft and appealing glow, which is quite distinctive from the brilliant sparkle of faceted stones.
Like other forms of opal, Chrysopal does not display any cleavage. This means it does not have natural planes along which it splits easily.
Chrysopal usually has a conchoidal fracture, which is a curved breakage surface resembling the inner curves of a seashell. This is typical of more brittle materials.
The specific gravity of Chrysopal typically ranges from about 2.1 to 2.2. This is relatively light, reflecting its significant water content.
Chrysopal, being an amorphous substance, does not exhibit double refraction. This is a characteristic feature of crystalline materials.
Chrysopal generally shows very little to no dispersion or fire, unlike its more famous counterpart, precious opal, which is known for vibrant color plays.
Chrysopal is amorphous, meaning it does not have a crystalline structure. This is typical of opal varieties.
Chrysopal often presents in greenish hues, which can range from pale to vibrant green, depending on the specific conditions of formation and trace elements.
This gemstone varies from opaque to translucent. The degree of transparency can affect the visual appeal and value of the stone.
Being amorphous, Chrysopal does not exhibit pleochroism. This optical phenomenon is generally associated with crystalline minerals.
Chrysopal may show weak fluorescence under ultraviolet light, but this can vary widely among specimens.
The toughness of Chrysopal is generally fair to good, which is typical for opal varieties. However, it can be prone to drying and cracking, known as “”crazing.””
Chrysopal’s tenacity is generally brittle, which is typical for opals due to their amorphous structure and high water content.
As an amorphous gemstone, Chrysopal does not have an optic sign, which is a characteristic of anisotropic or birefringent materials.
Chrysopal does not typically show a distinctive absorption spectrum, unlike some gemstones that can be identified by characteristic lines or bands.
Chrysopal is a form of hydrated silica, primarily SiO₂·nH₂O, with water content typically between 3% and 21%.
Chrysopal can sometimes exhibit a cat’s eye effect if it has parallel inclusions, but this is relatively rare compared to other gemstones known for this optical phenomenon.
Asterism, or the star effect, is not commonly observed in Chrysopal. This effect is more typically associated with crystalline gemstones.
While common in precious opals, iridescence is generally lacking in Chrysopal, which instead displays a more uniform coloration.
Chrysopal is not magnetic. This property is generally associated with gemstones containing iron or other magnetic elements.
Being composed predominantly of silica, Chrysopal is an electrical insulator.
Chrysopal is not radioactive. This property is generally considered in the context of minerals containing radioactive elements, which Chrysopal does not.