Taramellite, Ba4(Fe3+,Ti4+,Fe2+,Mg)4(B2SigO27)O2Clx, until recently known only at the type locality, Candoglia in Italy, has been found together with many other Ba-silicates at eight scattered localities in western North America. All of the taramellites from these localities are highly titanian and those in which Ti/Fe exceeds unity may be called titantaramellite. Contrary to the formerly current description, taramellite is not at all fibrous, but occurs in tabular to equidimensional orthorhombic crystals, in some occurrences with excellent morphology. Six of the North American occurrences are at or close to the contacts of large granitic bodies where zones or lenses within metamorphic rocks are composed largely of Ba-silicates among which sanbornite, BaSi2O5, is dominant. At one locality in Santa Cruz, California, taramellite has been found in large, ragged, crystals in a metamorphosed limestone which carries a wide variety of sulfides and sulfosalts. Finally, taramellite is a minor constitutent in complex veins in Franciscan enclaves within a large ultramafic body in San Benito County, California. Analyses and properties of taramellites at all eight localities are reported together with decriptions of each locality and data on the associated minerals.

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