Formula: FeAl₂(SO₄)₄ · 22H₂O

Species:

Colour: Colourless to white, yellowish, greenish; colourless in transmitted light.

Lustre: Silky

Hardness: 1½ – 2

Specific Gravity: 1.89

Crystal System: Monoclinic

Member of: Halotrichite Group; Halotrichite Group; Halotrichite-Pickeringite Series. Fe(II) analogue of Pickeringite.

Name: Named in 1839 by Ernst Friedrich Glocker from the Greek αλζ meaning salt and τρικοζ meaning hair. Latin form is “halotrichum,” which in turn is from the older German name “Haarsalz” (hair salt).