Phenakite
Species
Rare · Be₂SiO₄
Beryllium silicate forming colourless to pale crystals in granitic pegmatites. Its name, from the Greek for deceiver, recalls how easily clear crystals pass for quartz. Cut stones usually weigh one or two carats and rarely more than a dozen.
Identity
- Formula
- Be₂SiO₄
- Chemical class
- Silicate
- Also known as
- Phenacite
Crystallography
- Crystal system
- Trigonal
- Habits
- Prismatic, Rhombohedral
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 7.5
- Density
- 2.96 g/cm³
- Luster
- Vitreous
- Colors
- colorless, white, pale yellow, pink
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Igneous, Hydrothermal
- Host rocks
- Granite, Schist and gneiss
- Associated minerals
- Beryl, chrysoberyl, Topaz, Quartz
- Found in
- Pegmatite deposit
- Geography
- Russia, Brazil, USA, Norway, Madagascar
Classification
- Rarity
- Rare
- Gem quality
- Yes
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Phenakite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Phenakite. Gemdat.org (Hudson Institute of Mineralogy).
- Phénacite. Wikipédia, l'encyclopédie libre (fr).
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