Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Hexagonal
    Chemistry : Na₆Ca₂Al₆Si₆O₂₄(CO₃)₂
    Rarity : Uncommon

Cancrinite is a mineral typical of alkaline rocks (nepheline syenites and their pegmatites, ijolites, etc...), in which it can have a primary or secondary origin, by alteration of nepheline. Formerly designating a group, this name is now restricted to carbonate terms, chlorinated terms being called davyne. It was named in honor of Count Egor Frantsevich Kankrin, Russian Minister of Finance. Usually massive, cancrinite is rarely hexagonal prismatic crystals, ending in a flattened pyramid, which does not exceed 2 cm. Its color is variable: colorless, honey yellow, gray, green, blue to gray-blue, reddish. Easily altered, cancrinite transforms into a mixture of zeolite, carbonate and kaolinite.

Main photo: Cancrinite from Caspar Quarry, Ettringen, Germany © Stephan Wolfsried

Twins are rare and lamellar.

No fake identified for this mineral species.