At type locality (Ettringen, Rhine Province, Germany) in cavities of metamorphosed limestone inclusions in alkaline igneous rocks. Also in metamorphosed limestones.
Comments
South African material has yielded minute stones, some of which may have been labeled sturmanite.
Series to Sturmanite.
Sources
Ettringen, Germany: In tiny crystals.
Franklin, New Jersey: Minute crystals.
South Africa: Associated with sturmanite at the Jwaneng mine, near Hotazel. The sturmanite forms yellowish coatings, with ettringite cores.
Stone Sizes
Material from Ettringen and Franklin is microscopic. A 2.5 carat pale yellow ettringite was faceted from material found in the center of a mass of sturmanite from South Africa. This may be the largest known for the species.
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