Hydrogrossular Garnet Value, Price, and Jewelry Information

Hydrogrossular garnet cabochon, 24.43 cts, 33.6 x 16 mm, Peru. © The Gem Trader. Used with permission.

Hydrogrossular Garnet

Hydrogrossular differs from the other garnets in that it is never transparent. It ranges from translucent to opaque. The most common color is a bluish green, but they are also found in pink, white, and gray.

Hydrogrossular Garnet Information

Data Value
Name Hydrogrossular Garnet
Is a Variety of Grossular Garnet
Heat Sensitivity Some
Formula Ca3Al2(SiO4)3-x(OH)4x
Colors Bluish green, green, pink, white, gray
Fracture Conchoidal, splintery
Hardness 6.5-7.5
Cleavage None
Crystallography Isometric
Refractive Index 1.72-1.80
Birefringence None
Dispersion 0.028
Pleochroism None.
Optics Isotropic
Luster Waxy
Specific Gravity 3.40-3.70
Transparency Translucent to opaque
Birthstone January

Hydrogrossular differs from the other garnets in that it is never transparent. It ranges from translucent to opaque. The most common color is a bluish green, but they are also found in pink, white, and gray.

Because of its coloring and translucency, hydrogrossular is often used as a jade substitute. Large pieces are available, which lend themselves to carving.

Material from New Zealand is known as rodingite (N = 1.702, specific gravity 3.35). So-called Transvaal jade from South Africa occurs in green, gray-green, blueish, and pink colors. Compact and homogeneous, it may have a splintery fracture and waxy luster. The gray material contains zoisite. Pink material, containing Mn, has N = 1.675-1.705 and specific gravity of 3.27. The green, jade-like material has N = 1.728 and specific gravity 3.488.