Holtstamite
Holtstamite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₃Al₂(SiO₄)₂(OH)₄.
It crystallizes in the tetragonal crystal system (space group I4_1/acd). It is a member of the Garnet structural group.
Key properties: Mohs hardness 6; specific gravity 3.25; White streak; Vitreous luster; optically uniaxial.
IMA symbol Hts, IMA status: approved, named in 2003.
Found in a manganese-rich calc-silicate contact metamorphic rock.
It is found associated with Mn3+-bearing vesuvianite, calcite, henritermierite.
The mineral was named to honor Dr. Dan Holtstam (b. 1963) for his contributions to Swedish mineralogy and specifically Mn deposits of the Långban type.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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