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Name Origin | Magnesite is named in allusion to the composition (magnesium) |
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Chemical Formula | MgCO3 (magnesium carbonate) |
Color | Colorless, white, gray, yellowish to brown |
Hardness | 3.5 - 4.5 on Mohs Scale |
Crystal System | Hexagonal. Crystals very rare; massive, compact, fibrous. Some specimens may be transparent. |
Cleavage | Perfect rhombohedral; Brittle |
Specific Gravity (SG) | 3.0 - 3.12 |
Pleochroism | None |
Luster | vitreous to dull |
Stone sizes |
Largest known cut magnesite is 134.5 carats from brazil material. |
Occurrence | Magnesite occurs as an alteration product of magnesium-rich rocks or as beds in metamorphic rocks. It can also occur as a gangue mineral in hydrothermal ore deposits |
Treatment |
Because of it porosity liquids should be avoided |
Note: Transparent magnesite gems are both rare and beautiful. The huge birefringence is obvious even in small stones, and large gems have a sleepy look, or fuzziness, due to the doubling of back facets as seen through the table. Faceted magnesite is rarely seen, and the material is very difficult to cut. Cuttable crystals have been found at Bom Jesus Meiras, Brazil, and many other localities.
Photo Credit: www.shutterstone.com
References: 1- Color Encyclopedia of Gemstones, Joel E. Arem, VNR publications, New York.
References: 1- Color Encyclopedia of Gemstones, Joel E. Arem, VNR publications, New York.