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Glittering
Stones >> Crystal Habit
Glittering Stones Crystal habit
 In mineralogy, shape and size give mount to
evocative terms applied to the typical appearance, or habit of crystals
The many terms used by mineralogists to explain crystal
habits are very useful in communicating what specimens of a meticulous
mineral frequently look like. Recognizing numerous habits helps
a mineralogist to recognize a large number of minerals. Some habits
are characteristic of certain minerals, although the majority
minerals exhibit many conflicting habits which are influenced
by certain factors. Crystal habit might mislead
the inexperienced as a mineral's crystal
system could be hidden or even disguised.
Factors influence a crystal's habits include: a combination of
two or even more forms; trace impurities there during growth;
crystal twinning and growth conditions (i.e.,
heat, pressure, space). Minerals feel right to the same crystal
system do not necessarily exhibit the same habit. Some
habits of a stone are exclusive to its variety
and locality: For example, while most sapphires form
elongate barrel-shaped crystals, those establish
in Montana form stout tabular crystals. Ordinarily,
the latter habit is seen only in ruby. Sapphire
and also ruby are both varieties of the same
mineral; corundum.
Some minerals might replace other obtainable minerals while preserving
the original's habit: this procedure is called pseudomorphous
replacement. A classic example is tiger's eye quartz,
crocidolite asbestos restored by silica. While quartz typically
forms ethereal (well-formed), prismatic (elongate, prism-like)
crystals, in tiger's eye the
unique fibrous habit of crocidolite is preserved.
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