White acicular loughlinite from the TL in Wyoming (Westvaco Mine, Green River Basin, Sweetwater County, Wyoming, United States of America). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Loughlinite
Loughlinite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂Mg₃Si₆O₁₆·8H₂O.
It is a member of the Clay structural group.
Key properties: specific gravity 2.165; Silky luster; optically biaxial.
IMA symbol Lou, IMA status: approved, named in 1960.
Occurs as replacements in dolomitic medium- to low-grade oil shale of the Green River Formation (Sweetwater Co., Wyoming, USA).
It is found associated with Shortite, northupite, searlesite (Sweetwater Co., Wyoming, USA); sepiolite, analcime, montmorillonite, dolomite (Killik, Turkey).
The name refers to Dr. Gerald Francis Loughlin (1880–1946), Chief Geologist, U.S. Geological Survey.