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2008-05-14 03:00:23

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. With some exceptions, many mineral lovers consider the amphibole-group minerals not spectacular enough to be collected and displayed; indeed, they believe these dark minerals are significant only for professional mineralogists who like to classify them in groups and species or for the...


Latest Hornblende Reference Libraries

28_e9750264d5476c85f9be09d17bc6fd51
2005-05-26 12:03:39

Biotite is a common phyllosilicate mineral that contains potassium, magnesium, iron and aluminium. It is sometimes called "iron mica" and is found in granitic rocks, gneisses, and schists. Like other mica minerals, biotite has a highly perfect basal cleavage, its flexible sheets easily flaking off. It has a hardness of 2.5 - 3, a specific gravity of 2.7 - 3.1, is colored greenish to brown or black, and can be transparent to opaque. Biotite is occasionally found in large sheets, especially in...

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Word of the Day
malpais
  • The ragged surface of a lava-flow.
'Malpais' translates from Spanish as 'bad land.'