Chemical Composition | It is aluminum silicate having the chemical formula Al2 SiO5. |
Colours | Different shades of brown and green. Other colours are red, gray, orange and pink. |
Luster | Vitreous to glassy. |
Hardness | Varies between 6.5- 7.5. |
Specific Gravity | 3.1 to 3.2 |
Refractive Index | 1.632-1.650 |
Solid State | Transparent to translucent. |
Crystal System | Orthorhombic crystal system. |
Pleochroism | Very strong. |
Fractures | Uneven to sub conchoidal. |
Enhancement | It is sometimes enhance to improve the colour. |
Source | Brazil, Sri Lanka, UK, Spain, Australia, United States, India, Russia and China. |
Precautions | Needs only general gemstone precautions, nothing specific. |
