Hauyne
Mineral (Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
Also called Haüyne and Hauynite
About it
Small, vivid blue grains and dodecahedra in volcanic rocks of the Eifel, Germany, and the Alban Hills near Rome; prized as tiny faceted gems.
- Type
- Mineral
- Group
- Silicate (tectosilicate), sodalite group
- Formula
- (Na,Ca)4-8Al6Si6(O,S)24(SO4,Cl)1-2
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 2.44–2.5
- Streak
- bluish white
- Lustre
- vitreous (glassy), greasy
- Crystal system
- Isometric (cubic)
- Colours
- bright blue, greenish blue, white, grey, black
- Transparency
- transparent, translucent
- Cleavage and fracture
- distinct dodecahedral; conchoidal fracture
- Under UV light
- sometimes orange-pink under longwave UV
Typical values: real specimens vary. For more, see mindat.org.