Chalcedony Facts

Chalcedony Facts


Chalcedony  Physical Properties

Chemical Composition The chemical composition is Silicon dioxide and the chemical formula is SiO2.
Colours Varied colours.
Hardness Varies between 6.5 – 7 Mohs.
Refractive Index 1.543  – 1.554
Specific Gravity 2.65 – 2.67
Luster Waxy to dull.
Solid State Opaque to translucent. Few varieties can be transparent too.
Crystal System Tetrahedral crystal system.
Cleavage None
Heat Sensitive No
Fractures Conchoidal
Bi-refringence 0.009
Pleochroism None
Source Worldwide occurrence. Main producers are United States and Brazil.
Enhancement Not enhanced.
Precautions Only general gemstone precautions required.

NOTE – These properties are largely for the Chalcedony as a group name. It is common to almost all the varieties. However, few exceptions would always be present.

Interest Items: