Mineral description : Cancrinite

Yellow cancrinite from Alnö.

Mineral class	Silicates : Tekto silicates : Nefeline leucite sodalite group
Chemical formula	(Na,Ca)7Al6Si6O24(CO3SO4Cl)1.5-2.1-5H2O
Crystal system	Hexagonal
Habitus	Crystals rare, prismatic. Often as grains massive or veins.
Cleavage	Perfect prismatic. Fracture uneven.
Hardness	5-6
Density	2.42-2.51
Color	White, gray, yellow, orange, pink reddish or bluish.
Streak	White
Luster	Vitreous to greasy. Transparent to translucent.
Description
Occurance	In igneous rocks. As a primary mineral in alkalirich rocks or as an alteration product of nepheline. It could also occur in contact metamorphic limestones. Have also been found in gneisses.
Associates	Nepheline, Sodalite
Notes	Named after a Russian minister of finance, count G Cancrin (1774-1845). Soluble in hydrochloric acid, giving off gas. A siliceous gel is produced.
Locations	A not so common mineral Siksjöberg, Särna, Dalarna. In nepheline-syenites. Almunge area, Uppland. In nepheline-syenites. Alnö, Sundsvall, Medelpad. As yellow weins and concretions in Hörningsholm.

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