Andradite mineral - You can buy these samples

Andradite is a type of garnet.

In turn, it is divided into several sub-types:

     demantoid (green);
     topazolite (yellow-green);
     colophonite (reddish-brown, resinous sheen);
     gelletite (light green);
     melanitis (black, contains TiO2).

Andradite does not find practical application (with the exception of the most expensive variety - demantoid, which is used in jewelry). However, we love collectors.

You can see andradite stone for sale and buy it in the Minerals of Russia online store.

Physical properties of Andradite

General
Category	Garnet group
Formula (repeating unit)	Ca₃Fe₂(SiO₄)₃
IMA symbol	Adr
Strunz classification	9.AD.25
Crystal system	Cubic
Crystal class	Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m)
Space group	Ia3d
Unit cell	a = 12.056 Å; Z = 8
Identification
Color	Yellow, greenish yellow to emerald-green, dark green; brown, brownish red, brownish yellow; grayish black, black; may be sectored
Crystal habit	Commonly well-crystallized dodecahedra, trapezohedra, or combinations, also granular to massive
Cleavage	none
Fracture	conchoidal to uneven
Tenacity	Brittle
Mohs scale hardness	6.5 to 7
Luster	Adamantine to resinous, dull
Streak	White
Diaphaneity	Transparent to translucent
Specific gravity	3.859 calculated; 3.8–3.9 measured
Optical properties	Isotropic, typically weakly anisotropic
Refractive index	n = 1.887
Absorption spectra	demantoid – 440nm band or complete absorption at 440nm and below, may also have lines at 618, 634, 685, 690nm ^[2]
Major varieties
Demantoid	transparent light to dark green to yellow-green
Melanite	opaque black
Topazolite	transparent to translucent yellow, may show chatoyancy