Haüyne Crystal in a Vug of a Sanidinite
Haüyne Crystal in a Vug of a Sanidinite. Photo Copyright © Volker Betz

Haüyne (pronounced ah-WEEN) is a rather rare mineral belongs to the sodalite mineral group, which includes sodalite, haüyne, lazurite (a sulfide-bearing haüyne variety), and nosean. Together, these minerals comprise the popular gem rock known as lapis lazuli.

Haüynes have a slightly blueish to colorless streak. Since streak testing can damage or destroy a specimen and most gemstones leave a colorless streak, don't try this test on suspected haüynes.

Excellent intensive blue and gemmy crystal of haüyne in a vug of a sanidinite ejection block.
Formula: Na3Ca(Si3Al3)O12(SO4)
System: Isometric
Colour: Blue, white, grey, ...
Lustre: Vitreous, Greasy
Hardness: 5½ - 6

Locality: In den Dellen quarries, Niedermendig, Mendig, Laach lake volcanic complex, Eifel, Rhineland-Palatinate, Germany