Latest Inosilicates Stories
MELBOURNE, Australia, Oct.
By Lupulescu, Marian Readers may wonder why we need an article about amphiboles in this publication. There are considerable concerns about this topic, and I want to comment briefly about two of them.
Amphibole defines an important group of dark-colored rock-forming inosilicate minerals composed of double chain SiO4 tetrahedra linked at the vertices and generally containing ions of iron and/ or magnesium in their structures. In chemical composition and general characteristics they are very similar to the pyroxenes and, like them, fall into three series according to their system of crystallization. The chief difference between amphiboles and pyroxenes is in cleavage: amphiboles form oblique...
Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. It occurs as foliated to fibrous masses, its monoclinic crystals being so rare as to be almost unknown. It has a perfect basal cleavage, the folia non-elastic although slightly flexible. It is sectile and very soft, with a hardness of 1 (Talc is the softest known solid). It has a specific gravity of 2.5 - 2.8, a waxlike or pearly luster, and is translucent to opaque. Its color...
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