Goldmanite

It was first described in 1964 for an occurrence in the Laguna District, Cibola County, New Mexico and is named after Marcus Isaac Goldman (1881–1965), an American petrologist. ==Occurrence==

In addition to the type location in the Sandy mine in New Mexico, it has been reported from Coat-an-Noz, Cotes-du-Nord, France; in drill core from the North Sea; from Klatovy, Czech Republic; Ishimskaya Luka, northern Kazakhstan; the Slyudyanka complex, Sayan Mountains, near Lake Baikal region of Russia and the Yamoto mine, Kagoshima Prefecture, Japan. ==Composition==

Goldmanite is composed of calcium (24.79%), aluminium (3.34%), vanadium (12.6%), iron (2.3%), silicon (17.37%), and oxygen (39.59%). Its chemical formula is {{chem2|Ca3(V^{3+},Al,Fe^{3+})2(SiO4)3}}. ==Properties==

The approximate density (3.74±.03) of goldmanite was determined by finding the density of diluted Clerici solution in which small fragments remained suspended. Because of fine grain size, more accurate determination of density was not attempted. The calculated density (3.737) agrees with the approximate value. The index of refraction was found by immersion to be 1.821±.001, using sodium light and adjusting for small temperature changes. Like so many calcium garnets, goldmanite was found to be weakly anisotropic. The cell edge of goldmanite is 12.011 Å, as determined by x-ray powder diffraction analysis. ==References==