Difference between revisions of "Chalcedony"
From The Gemology Project
m |
|||
Line 1: | Line 1: | ||
{{chalcedony}} | {{chalcedony}} | ||
− | Chalcedony is microcrystalline (cryptocrystalline) [[quartz]]. The | + | Chalcedony is microcrystalline (cryptocrystalline) [[quartz]]. The name is often used to encompass all varieties of microcrystalline quartz such as jasper, carnelian, chrysoprase and bloodstone. The mineral is very abundant and found all over the world. The most common variety is a muted blue-gray tone (unnamed) found in geodes and vugs. |
Latest revision as of 17:59, 22 December 2006
Chalcedony | |
---|---|
Chemical composition | Silicon dioxide SiO2 |
Crystal system | Trigonal |
Habit | Aggregate |
Fracture | Conchoidal |
Hardness | 6.5-7 |
Refractive index | 1.535 - 1.539 |
Specific gravity | 2.60 |
Lustre | Vitreous |
Chalcedony is microcrystalline (cryptocrystalline) quartz. The name is often used to encompass all varieties of microcrystalline quartz such as jasper, carnelian, chrysoprase and bloodstone. The mineral is very abundant and found all over the world. The most common variety is a muted blue-gray tone (unnamed) found in geodes and vugs.