Your Purchases
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 silica-rich solutions deposit microscopic spheres of silica in a regular, cubic close-packed arrangement. This unique structure creates distinct blocks of color, typically 1-5 millimeters in size, that remain stable and clearly delineated rather than the flowing or flashy patterns seen in common opals. The most valuable specimens originate from Australia’s Lightning Ridge region, displaying vivid reds and blues against a dark body tone.
This gem’s distinctive pattern results from an unusually ordered arrangement of silica spheres of uniform size, creating larger domains of diffraction gratings that produce the characteristic angular color blocks. The name derives from the resemblance to the diamond-patterned costume of the Harlequin character from Italian commedia dell’arte.
Harlequin Opal is typically a natural gemstone.
Common names for Harlequin Opal include Fire Opal, Girasol Opal, and Matrix Opal.
Harlequin opal, like other opals, has a relatively low hardness rating on the Mohs scale, typically around 5.5 to 6.5. This makes it somewhat susceptible to scratches and abrasion, which is important to consider for jewelry that will be worn frequently.
The refractive index of Harlequin opal ranges from approximately 1.44 to 1.46. This is a key optical property that influences how much light is bent when entering the stone.
Harlequin opal exhibits a characteristic subvitreous to waxy luster, which contributes to its unique visual appeal. The quality of luster can vary slightly depending on the opal’s structure and composition.
Opals, including Harlequin opal, generally do not have cleavage. This refers to the way a mineral breaks along certain planes. Instead, opal breaks irregularly, following its amorphous structure.
The typical fracture in a Harlequin opal is conchoidal, which means it has smooth, curved surfaces similar to the fracture of glass. This is a common feature in amorphous and cryptocrystalline materials.
Harlequin opal has a specific gravity generally between 2.1 and 2.3, which is relatively low compared to many other gemstones. This property helps in identifying the gemstone and assessing its quality.
Opal, including Harlequin opal, is isotropic and does not exhibit double refraction. This is due to its amorphous nature.
Harlequin opal is particularly noted for its spectacular play of color or “”fire,”” which is an internal dispersion of light into colors of the spectrum. This property is highly variable and is one of the most sought-after features in opals.
Harlequin opal is amorphous, meaning it does not have a crystalline structure. This is characteristic of all types of opal.
The defining characteristic of Harlequin opal is its color play, which displays a vivid, checkerboard-like pattern of bright, multi-colored patches. The background color can vary widely.
Opals can range from completely opaque to highly transparent. Harlequin opals are generally opaque to translucent, depending on the particular stone and its structure.
Harlequin opal does not exhibit pleochroism due to its amorphous nature. Pleochroism is the ability to show different colors when viewed from different angles, typically seen in crystalline materials.
Some opals, including certain Harlequin opals, may exhibit fluorescence under ultraviolet light, typically showing a white or greenish glow.
Opal has fair to good toughness, but its relatively low hardness and common presence of internal stresses can make it prone to cracking or chipping under impact.
Opals are generally brittle, and Harlequin opal is no exception. Care should be taken when setting and wearing opal jewelry to avoid damaging the stone.
Being isotropic, Harlequin opal has no optic sign, which is consistent with its amorphous structure.
Harlequin opals do not typically display a characteristic absorption spectrum due to their amorphous nature and unique color play.
Opal is a hydrated form of silica (SiO2·nH2O). The water content can range from 3 to 21% by weight, but it is usually between 6% and 10%.
While typically not applicable to Harlequin opal, some opals can exhibit chatoyancy when cut appropriately and when fibrous inclusions are present.
Asterism is not typically associated with Harlequin opal. This effect is generally seen in stones like sapphire or ruby, which have a different crystalline structure.
The play of color in Harlequin opal is a form of iridescence, arising from the diffraction of light by the internal structure of the opal.
Harlequin opal is non-magnetic, consistent with its silica composition.
Being composed mostly of silica, Harlequin opal has very low electrical conductivity.
Harlequin opal is not radioactive.
