Orange microcrystal of verplanckite from the TL in California (Fresno County, California, United States of America). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Verplanckite
Verplanckite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ba₄Mn²⁺₂Si₄O₁₂(OH,H₂O)₃Cl₃.
It crystallizes in the hexagonal crystal system (space group P6/mmm).
Key properties: Mohs hardness 2.5–3; specific gravity 3.52; Pale orange streak; Vitreous luster; optically uniaxial.
IMA symbol Vpk, IMA status: approved, named in 1964.
Found in thin layers in a metamorphic sanbornite-quartz rock.
It is found associated with Quartz, sanbornite, celsian, diopside, taramellite, fresnoite, muirite, traskite, pyrrhotite, pyrite.
The name refers to William E. Ver Planck (1916–1963), geologist of the California Division of Mines & Geology, California, USA.