Moissanite
In gemology moissanite is classified as synthetic - although it is found in nature, but the natural crystals are of no practical importance because of their small size.
The natural mineral was first found as tiny crystals - small green platelets of silicon carbide, in iron meteorite fragments at Diablo Canyon in Arizona by Dr. Ferdinand H. Moissan. The mineral was named in his honour.
Synthetic moissanite is a Diamond simulant. Most of the properties of diamond are quite well imitated, but moissanite may be detected easily by a gemmologist with simple equipment. Synthetic moissanite is often colourless, sometimes brown, green, yellow and blue but the colours are not very strong.
The natural mineral was first found as tiny crystals - small green platelets of silicon carbide, in iron meteorite fragments at Diablo Canyon in Arizona by Dr. Ferdinand H. Moissan. The mineral was named in his honour.
Synthetic moissanite is a Diamond simulant. Most of the properties of diamond are quite well imitated, but moissanite may be detected easily by a gemmologist with simple equipment. Synthetic moissanite is often colourless, sometimes brown, green, yellow and blue but the colours are not very strong.
| General Information | ||
|---|---|---|
| Chemical Formula |
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| Moissanite Treatments | ||
| A near-colourless moissanite has been heat-treated, causing a brownish colour across all the facets. Cleaning and hand-polishing the samples, using cerium oxide on leather, restored the reflectivity to 98% of the non-treated material. If heating forms part of any testing experiment on a suspected moissanite, the gemmologist should remember that surface oxidation could occur and keep the level of heating to a minimum. The colour of the surface might undergo alteration. - Michael O’Donoghue, Gems, Sixth Edition (2006), p. 89 | ||
| Synthetic Moissanite | ||
| The method of synthesis is probably a modified form of the flux-melt process. - Gemstones, Arthur Thomas, 2009, p 207 | ||
| Physical Properties of Moissanite | ||
| Mohs Hardness | 9 to 9.5, Blue Chart Gem Identification (2010) More from other references | |
| Specific Gravity | 3.17 to 3.24, Blue Chart Gem Identification (2010) More from other references | |
| Cleavage Quality | None, Gemstones (2009) More from other references | |
| Fracture | Conchoidal, Handbook of Mineralogy (2001) | |
| Heat Sensitivity | May turn yellowish if heated (250 watt bulb), Blue Chart Gem Identification (2010) | |
| Optical Properties of Moissanite | ||
| Refractive Index | 2.648 to 2.691, Blue Chart Gem Identification (2010) More from other references | |
| Optical Character | Uniaxial/+, Blue Chart Gem Identification (2010) More from other references | |
| Birefringence | 0.043, Blue Chart Gem Identification (2010) DoublingMore from other references | |
| Pleochroism | Nil, Gemstones (2009) More from other references | |
| Dispersion | 0.104, Gemstones (2009) | |
| Colour | ||
| Colour (General) | Colourless, greenish, yellowish, Gemmological Tables (2004) More from other references | |
| Transparency | Transparent, Gemmological Tables (2004) More from other references | |
| Lustre | Adamantine, Gemstones (2009) More from other references | |
| Fluorescence & other light emissions | ||
| Fluorescence (General) | Usually dark orange or light blue, Blue Chart Gem Identification (2010) | |
| Crystallography of Moissanite | ||
| Crystal System | Hexagonal, Blue Chart Gem Identification (2010) More from other references | |
| Habit | Tabular, Gemstones (2009) More from other references | |
| Geological Environment | ||
| Where found: | A rare mineral: formed in an iron meteorite; as inclusions in diamond; in diamondiferous kimberlites and lamproites, and in eclogite; in volcanic breccias and rhyolite; in alluvium., Handbook of Mineralogy (2001) | |
| Inclusions in Moissanite | ||
| Inclusions: white needles - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 32 | ||
| Further Information | ||
| Mineral information: | Moissanite information at mindat.org | |