Andradite

Andradite

Chemical Formula:  Ca3Fe3+2Si3O12

Chemical Composition:  Calcium iron silicate

Crystal System:  Cubic (Isometeric)

Mineral Group:  Garnet

Varieties of Andradite:  Demantoid, Melanite, Topazolite

Hardness:  6 — 7

Density/Specific Gravity:  3.7 — 4.1

Refractive Index:  1.88 — 1.94

Double Refraction:  None

Absorption Spectra:  701, 693, 640, 622, 443

Colour:  Black, brown, yellow-brown, greenish yellow, lemon yellow

Pleochroism:  None

Transparency:  Transparent, translucent, opaque

Lustre:  Vitreous (glassy), adamantine (diamond like – non-metallic) 

Luminescence:  None

Cleavage:  None

Fracture:  Conchoidal

Countries:  Deposits are widespread. China, France, Germany, Italy, Korea, Mexico, Norway, Romania, Russia, South Africa, Switzerland, USA, Zaire

Notes:  Demantoid is the most valuable garnet and has a diamond like lustre. Deposits found in China, Korea, Russia, USA, and Zaire.
Melanite deposts are found in France, Germany, Italy, and Colorado.
Topazolite looks like topaz and is yellow to lemon yellow in colour. Deposits found in California, the Italian Alps, and Switzerland.

andradite
Select your currency