Agate
(ag'-ate)
13th c.; lat. acathes, gr. akhatês
A variety of chalcedony with colored bands or irregular clouding used in jewelry and also to make fine cameos, bowls, etc.
Color
Translucent , all colors in bands or layers
Family
Chalcedony - Cryptocristalline quartz
Chemical composition
SiO2
Hardness (Mohs scale)
6,5 - 7
Specific gravity
2,60 ±0,05
Refractive index
1,537 ±0,02
Optical character
None (aggregate)