Properties
| Category | Nesosilicate |
|---|---|
| Formula | Be2SiO4 |
| Crystal system | Trigonal |
| Color | Colorless, yellow, pink, brown |
| Crystal habit | Tabular, prismatic to acicular crystals often as columnar aggregates, as spherulites and granular |
| Cleavage | Distinct on {1120}, imperfect on {1011} |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 7.5–8 |
| Luster | Vitreous |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 2.93–3.00 |
From the Wikipedia article
Phenakite or phenacite is a fairly rare nesosilicate mineral consisting of beryllium orthosilicate, Be2SiO4. Occasionally used as a gemstone, phenakite occurs as isolated crystals, which are rhombohedral with parallel-faced hemihedrism, and are either lenticular or prismatic in habit: the lenticular habit is determined by the development of faces of several obtuse rhombohedra and the absence of prism faces. There is no cleavage, and the fracture is conchoidal. The Mohs hardness is high, being 7.5–8; the specific gravity is 2.96. The crystals are sometimes perfectly colorless and transparent, but more often they are greyish or yellowish and only translucent; occasionally they are pale rose-red. In general appearance the mineral is not unlike quartz, for which indeed it has been mistaken. Its name comes from Ancient Greek: φέναξ, romanized: phénax, meaning "deceiver" due to its close visual similarity to quartz, named by Nils Gustaf Nordenskiöld in 1833.
Source
Source record: crystal-compendium/phenakite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Phenakite — revision id 1377111630. Text and properties from Wikipedia, licensed CC BY-SA 4.0.