Periclase
Periclase is named after Greek "peri" - around and "klasis" - breaking, alluding to its perfect cubic cleavage.
Well-developed crystals can be very attractive. Periclase is occasionally cut as gemstones, but it has limited colour range and its hardness is not particularly high.
Synthetic periclase is often used as a simulant for other gemstones.
Well-developed crystals can be very attractive. Periclase is occasionally cut as gemstones, but it has limited colour range and its hardness is not particularly high.
Synthetic periclase is often used as a simulant for other gemstones.
| General Information | |||||||
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| Chemical Formula |
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| Photos of natural/un-cut material from mindat.org | |||||||
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| Synthetic Periclase | |||||||
| Synthetic periclase: MgO; Cubic; Green, colourless, transparent; Hardness 6; RI 1.738; Isotropic; SG 3.75; Cleavage perfect - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 24 | |||||||
| Physical Properties of Periclase | |||||||
| Mohs Hardness | 5.5 to 6, Blue Chart Gem Identification (2010) More from other references | ||||||
| Specific Gravity | 3.7 to 3.9, Gemstones of the world (2001) More from other references | ||||||
| Cleavage Quality | Perfect, Gemmological Tables (2004) More from other references | ||||||
| Optical Properties of Periclase | |||||||
| Refractive Index | 1.735 to 1.738, Blue Chart Gem Identification (2010) More from other references | ||||||
| Optical Character | Isotropic, Blue Chart Gem Identification (2010) Anomalous double refraction | ||||||
| Colour | |||||||
| Colour (General) | Yellowish, gray-green, colourless, Gemstones of the world (2001) More from other references | ||||||
| Transparency | Transparent, Gemstones of the world (2001) More from other references | ||||||
| Lustre | Vitreous, Handbook of Mineralogy (2001) | ||||||
| Fluorescence & other light emissions | |||||||
| Fluorescence (General) | Inert to whitish, Blue Chart Gem Identification (2010) | ||||||
| Crystallography of Periclase | |||||||
| Crystal System | Isometric, Blue Chart Gem Identification (2010) More from other references | ||||||
| Habit | Masses or small octahedra and other forms, Gems, Sixth Edition (2006) More from other references | ||||||
| Geological Environment | |||||||
| Where found: | A product of the high-temperature metamorphism of magnesian limestones and dolostone., Handbook of Mineralogy (2001) | ||||||
| Further Information | |||||||
| Mineral information: | Periclase information at mindat.org | ||||||
