Riversideite Locality: Crestmore quarries, Crestmore, Riverside County , California , USA ( Locality at mindat.org ) Size: 7.6 x 7.5 x 4.4 cm. Named after its discovery locality circa 1917, this is an old matrix specimen showing several veins of striated, parallel-grown crystals of this rare silicate. The Riversideite is embedded in matrix with gemmy olive-green vesuvianite crystals. Ex. Philadelphia Academy of Sciences and Smithsonian Institution Collections. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Riversideite
Riversideite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₅Si₆O₁₆(OH)₂·2H₂O.
It is a member of the Tobermorite structural group.
Key properties: Silky luster; optically biaxial.
IMA symbol Rsd, IMA status: questionable, named in 1917.
Occurs as intimate intergrowths with apatite, in veinlets cutting contact metamorphosed limestone (Crestmore, California, USA).
It is found associated with Apatite, vesuvianite, diopside, calcite, wollastonite (Crestmore, California, USA).
The name refers to the first-noted occurrence in Riverside Co., California, USA.