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Hydrogrossular (variety of Grossular Garnet)
Current inventory:  0 gems

Hydrogrossular (Garnet)

Hydrogrossular is named for hydroxide (OH) partially replacing silica (SiO4) and its relationship with Grossular. Grossular is named from the Latin "Ribes Grossularium", the botanical name for "gooseberry" in reference to its typical greenish color because the original specimens were this color.

Discovery year unknown;   IMA status: Not Valid (variety of Grossular Garnet)





Chemical Formula:

Ca3Al2(SiO4)3-x(OH)4x + Cr, Fe


Calcium Aluminum Silicate Hydroxide + traces of chromium and/or iron



More Information




Hydrogrossular is a variety of Grossular Garnet.
For more information please see the
Grossular Garnet information page.


Achtaragdite, African Jade, Transvaal Jade

Additional Information:  (Hydrogrossular)  (Grossular-Hibschite Series)  (Grossular)  (Grossular)

View mineral photos:

Grossular Mineral Photos and Locations



Hydrogrossular is a calcium aluminium variety of
Grossular Garnet with hydroxide (OH) partially replacing silica (SiO4). The identity of the members of the hydro-garnet family (Grossular, Hydrogrossular, Hibschite and Katoite) depend on the degree of substitution of hydroxide for silica.

Hydrogrossular is typically translucent to opaque, rarely transparent, and found in various shades of green to bluish green, pink, white and gray. The green color is due to the presence of chromium and/or possibly iron. Pink Hydrogrossular is colored by the presence of manganese. Green Hydrogrossular may contain small dark gray to black inclusions. Opaque to translucent Hydrogrossular may look similar to Jade but has no relationship to Jade. Hydrogrossular has been incorrectly referred to as Transvaal Jade or African Jade.

Hydrogrossular is found in massive crystal habit, sometimes intergrown in with Idocrase. Hydrogrossular is occassionally available as cabochons but rarely available as clean, transparent, faceted gemstones. These rare, transparent gems are a beautiful yellowish green with slight sleepiness similar to fine Prehnite gems. The main source of these beautiful gems is Achtaragda River mouth, Wilui River Basin, Saha Republic, Eastern-Siberian Region, Russia.

Sources for green and pink hydrogrossular are Canada, Russia, South Africa, and the United States. White Hydrogrossular is found in Burma and China.

gems for sale:

We have not photographed our Hydrogrossular gems yet. Please check back soon.


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