Class: Silicates
Group: Sodalite
Original description: Bruun-Neergard, T. C., 1807. De la haüyne, nouvelle substance minérale — Journal des Mines 21: 365 [
view in ‘Library’].
Type locality: ‘les environs du lac de Nemi’ [Lake Nemi], Alban Hills, Lazio, Italy (
Bruun-Neergard, 1807: 365).
Type material: unknown.
Etymology: named after Abbé René Just Haüy, French mineralogist, father of the modern crystallography.
Distribution: China; Germany: Eifel district; Italy: Lazio; USA, and others (
Anthony et al., 2001—2005).
Chemistry
(Na,Ca)4-8(Al6Si6O24)(SO4,S,Cl)1-2
Essential elements: oxygen (O), sodium (Na), aluminium (Al), silicon (Si), sulphur (S), chlorine (Cl), calcium (Ca).
Crystal data
Crystallography: isometric — hextetrahedral.
Crystal habit: crystals dodecahedra or pseudo-octahedra, to 3 cm; in rounded grains.
Twinning: on {111}, common, rarely as penetration twins; also as polysynthetic or contact twins (
Anthony et al., 2001—2005).
Material from ‘Repository’