nHumite(Min) A mineral of a transparent vitreous brown color, found in the ejected masses of Vesuvius. It is a silicate of iron and magnesia, containing fluorine.
Century Dictionary and Cyclopedia
nhumiteOriginally, a mineral from Vesuvius, occurring in small crystals yellow to brown in color, and belonging, as was believed, to three types of crystalline form. It was regarded as identical with chondrodite. At present these three varieties are accepted as distinct species or subspecies, and are called humite, chondrodite, and clinohumite. The name humite includes only the kind crystallizing in the orthorhombic system; the other two are monoclinic, but differ in angles and planes. They have all nearly the same chemical composition, being fluosilicates of magnesium and iron. See chondrodite.
nhumiteThe relation in chemical composition of the species of the humite group is shown by the following formula, established by Penfield and Howe: chondrodite, Mg3[Mg(F1OH)]2[SiO4]2; humite, Mg5[Mg(F1OH)]2[SiO4)3; clinohumite, Mg7[Mg(F1OH))2[SiO4]4. In these formulas the magnesium atoms present are, respectively, 5, 7, and 9, and these numbers also express the ratio of the vertical crystallographic axes of the three species. The fourth possible compound, Mg[Mg(F1OH)]2SiO4. is probably represented by the species prolectite, which, though not yet analyzed, has been shown (Sjögren) to be crystallographically the first member of this series whose vertical axes are in ratio of 3:5:7:9. See prolectite.
Webster's Revised Unabridged Dictionary
Named after Sir A. Hume,
The name humite, after Sir Abraham Hume, Bart.
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