Grossularite
Grossularite is a calcium-aluminium garnet with the formula Ca3Al2(SiO4)3, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossularite is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Because of its inferior hardness to zircon, which the yellow crystals resemble, they have also been called hessonite from the Greek meaning inferior. Grossularite is found in contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite.
Grossularite is a calcium-aluminium garnet with the formula Ca3Al2(SiO4)3, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossularite is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Because of its inferior hardness to zircon, which the yellow crystals resemble, they have also been called hessonite from the Greek meaning inferior. Grossularite is found in contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite.
Uvarovite is a calcium chromium garnet with the formula Ca3Cr2(SiO4)3. This is a rather rare garnet, bright green in color, usually found as small crystals associated with chromite in peridotite, serpentinite, and kimberlites. It is found in crystalline marbles and schists in the Ural mountains of Russia and Outokumpu, Finland
One of the most sought after varieties of gem garnet is the fine green grossular garnet from Kenya and Tanzania called tsavorite. This garnet was discovered in the 1960s in the Tsavo area of Kenya, from which the gem takes its name
Less common spcies
Calcium in A site
Goldmanite: Ca3V2(SiO4)3
Kimzeyite: Ca3(Zr,Ti)2[(Si,Al,Fe3+)O4]3
Morimotoite: Ca3Ti4+Fe2+(SiO4)3
Schorlomite: Ca3(Ti4+,Fe3+)2[(Si,Ti)O4]3
Hydroxide bearing - calcium in A site
Hydrogrossular: Ca3Al2(SiO4)3-x(OH)4x
Hibschite: Ca3Al2(SiO4)3-x(OH)4x (where x is between 0.2 and 1.5)
Katoite: Ca3Al2(SiO4)3-x(OH)4x (where x is greater than 1.5)
Magnesium or manganese in A site
Knorringite: Mg3Cr2(SiO4)3
Majorite: Mg3(Fe,Al,Si)2(SiO4)3
Calderite: Mn3Fe3+2(SiO4)3
Knorringgite
Knorringite is a magnesium chromium garnet with the formula Mg3Cr2(SiO4)3. Pure knorringite never occurs in nature. Garnet with high knorringite content may be generated only under high pressure. Knorringite is basically pyrope with a very high chromium content and is often found in kimberlites. It is used as an indicator mineral in the search for diamonds
Calcium in A site
Goldmanite: Ca3V2(SiO4)3
Kimzeyite: Ca3(Zr,Ti)2[(Si,Al,Fe3+)O4]3
Morimotoite: Ca3Ti4+Fe2+(SiO4)3
Schorlomite: Ca3(Ti4+,Fe3+)2[(Si,Ti)O4]3
Hydroxide bearing - calcium in A site
Hydrogrossular: Ca3Al2(SiO4)3-x(OH)4x
Hibschite: Ca3Al2(SiO4)3-x(OH)4x (where x is between 0.2 and 1.5)
Katoite: Ca3Al2(SiO4)3-x(OH)4x (where x is greater than 1.5)
Magnesium or manganese in A site
Knorringite: Mg3Cr2(SiO4)3
Majorite: Mg3(Fe,Al,Si)2(SiO4)3
Calderite: Mn3Fe3+2(SiO4)3
Knorringgite
Knorringite is a magnesium chromium garnet with the formula Mg3Cr2(SiO4)3. Pure knorringite never occurs in nature. Garnet with high knorringite content may be generated only under high pressure. Knorringite is basically pyrope with a very high chromium content and is often found in kimberlites. It is used as an indicator mineral in the search for diamonds
Source from Wikipedia
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