Dark blue microcrystals of stringhamite associated to sky blue acicular crystals of whelanite. — Photo: David Hospital · CC BY-SA 4.0
Whelanite
Whelanite is an IMA-recognized mineral species in the silicate class, with the chemical formula Cu₂Ca₆[Si₆O₁₇(OH)](CO₃)(OH)₃(H₂O)₂.
It crystallizes in the orthorhombic crystal system (space group Pn2n).
Key properties: Mohs hardness 2.5; specific gravity 2.74; Pale blue streak; Vitreous luster; optically biaxial.
IMA symbol Wla, IMA status: approved, named in 1977.
Found in a copper-rich, diopside-garnet-magnetite contact metamorphic rock (skarn).
It is found associated with Thaumasite, stringhamite, kinoite, diopside, garnet (grossular-andradite), goethite, magnetite, tenorite, chrysocolla (Bawana mine); gilalite, ruizite.
The mineral was named to honor James A. Whelan (1928- 2003), professor of mineralogy (1958 to 1992), University of Utah, Salt Lake City, Utah, USA.