cyanotrichite
Sign in to saveCyanotrichite is a hydrous copper aluminium sulfate mineral with formula Cu4Al2[(OH)12|SO4]·2H2O, also known as lettsomite. Cyanotrichite forms velvety radial acicular crystal aggregates of extremely fine fibers. It crystallizes in the monoclinic system and forms translucent bright blue acicular crystal clusters or drusey coatings. The Mohs hardness is 2 and the specific gravity ranges from 2.74 to 2.95. Refractive indices are nα = 1.588 nβ = 1.617 nγ = 1.655.
Key facts
- Mineral.caption
- Radiating sprays of cyanotrichite needles on matrix from the old Grand Canyon Mine now within Grand Canyon National Park (size: 3.8 × 3.7 × 1.2 cm)
- Mineral.category
- Sulfate minerals
- Mineral.formula
- Cu4Al2[(OH)12
- Mineral.IMAsymbol
- Cya
- Mineral.strunz
- 7.DE.10
- Mineral.system
- Monoclinic
- Mineral.class
- Prismatic (2/m) (same H-M symbol)
- Mineral.symmetry
- C2/m
- Mineral.unit cell
- a = 10.16 Å, b = 12.61 Å, c = 2.9 Å; Z = 1
- Mineral.color
- Sky-blue, azure-blue
- Mineral.habit
- Acicular crystals and fibrous aggregates; incrustations
- Mineral.fracture
- Uneven
- Mineral.mohs
- 1–3
- Mineral.luster
- Silky
- Mineral.streak
- Light blue
- Mineral.diaphaneity
- Transparent to translucent
- Mineral.gravity
- 2.76
- Mineral.opticalprop
- Biaxial (+)
via Wikipedia infobox
Wikidata facts
- Named after
- hair
- Image
- Cyanotrichite-Malachite-199581.jpg
Show 9 more facts
- Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
- 7.DE.10
- Commons category
- Cyanotrichite
- Nickel-Strunz 9th edition (updated 2009)
- 7.DE.10
- crystal system
- orthorhombic crystal system
- streak color
- light blue
- Mohs' hardness
- 2
- IMA Mineral Symbol
- Cya
- chemical formula
- Cu₄Al₂SO₄(OH)₁₂·2H₂O
- Strunz 8th edition (series ID, updated)
- VI/D.03
Sources (2)
via Wikidata · CC0
~1 min read
Encyclopedic overview
2 sectionsContents
- Occurrence and discovery
- References
Cyanotrichite is a hydrous copper aluminium sulfate mineral with formula Cu4Al2[(OH)12|SO4]·2H2O, also known as lettsomite. Cyanotrichite forms velvety radial acicular crystal aggregates of extremely fine fibers. It crystallizes in the monoclinic system and forms translucent bright blue acicular crystal clusters or drusey coatings. The Mohs hardness is 2 and the specific gravity ranges from 2.74 to 2.95. Refractive indices are nα = 1.588 nβ = 1.617 nγ = 1.655.
==Occurrence and discovery== It is an oxidation product of primary copper mineralization in a weathering environment with abundant aluminium and sulfate. Associated minerals include brochantite, spangolite, chalcophyllite, olivenite, tyrolite, parnauite, azurite and malachite.
Excerpted from Wikipedia’s “cyanotrichite” article, available under the CC BY-SA 4.0 licence.