SCAPOLITE, Mpapwa Tanzania (thumbnail)

Scapolites, derived from the Greek words for "rod" and "stone," represent a category of silicate minerals that form rocks and consist of aluminum, calcium, and sodium silicate, along with chlorine, carbonate, and sulfate. The two primary endmembers of this group are meionite, with the formula Ca4Al6Si6O24CO3, and marialite, represented as Na4Al3Si9O24Cl. Additionally, silvialite, with the composition (Ca,Na)4Al6Si6O24(SO4,CO3), is also acknowledged as a member of the scapolite group.

 

From the former Schneider's Rocks & Minerals Collection, Poway CA, USA