Hyalite
Hyalite (Greek - glass stone) is water-clear, glass-like and is generally considered the purest and clearest Opal variety. As a cut gem, it can be confused with glass.
Hyalite Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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Hyalite Gemstones by Size
This table shows distribution of Hyalite gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.96 cts
Heaviest:18.18 cts
Average:4.51 cts
Total photos:15
Do you have a larger Hyalite? Why not upload a photo?
| General Information | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| A variety or type of: | Common Opal, which is a variety of Opal | |||||||||
| Chemical Formula |
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| Hyalite Simulants | ||||||||||
| As a cut gem, it can be confused with glass. - Opal, Lithographie, 2007 | ||||||||||
| Physical Properties of Hyalite | ||||||||||
| Mohs Hardness | 5.5 to 6.5, Gemstones of the world (2001) | |||||||||
| Tenacity | Brittle, Gemstones of the world (2001) | |||||||||
| Cleavage Quality | None, Gemstones of the world (2001) | |||||||||
| Fracture | Conchoidal,Splintery, Gemstones of the world (2001) | |||||||||
| Heat Sensitivity | Sensitive, becomes soft and breaks up, Opal (2007) | |||||||||
| Optical Properties of Hyalite | ||||||||||
| Refractive Index | 1.37 to 1.52, Gemstones of the world (2001) | |||||||||
| Birefringence | None, Gemstones of the world (2001) | |||||||||
| Colour | ||||||||||
| Colour (General) | Colourless with strong sheen, Gemstones of the world (2001) | |||||||||
| Transparency | Transparent,Translucent, Gemstones of the world (2001) | |||||||||
| Fluorescence & other light emissions | ||||||||||
| Fluorescence (General) | Shows brilliant green fluorescence, especially under SW, due to uranium impurities., Opal (2007) | |||||||||
| Crystallography of Hyalite | ||||||||||
| Crystal System | Amorphous, Gemstones of the world (2001) | |||||||||
| Habit | Usually takes globular, botryoidal forms, Opal (2007) | |||||||||
| Further Information | ||||||||||
| Mineral information: | Hyalite information at mindat.org | |||||||||