Scalenohedral: A fancy shape gemstone made up of 12 facets, each shaped like a scalene triangle. Crystal points with triangular facets are said to be scalenohedral.
Scalloped: An ornamental border consisting of a series of curved projections.
Left: a scalenohedral crystal to 15mms with a final coating of tiny hexagonal prismatic crystals (see above)
from the Corrantee Mine.
Right: a "coronet" growth on the top of hexagonal prisms
(as seen in the UV calcite photos above) ...
Hexagonal-scalenohedral:
This has two principal forms under the class namely:
rhombohedron and
the hexagonal scalenohedron ...
Hexagonal-scalenohedral class. The first to consider are those forms with the symmetry - 3 2/m (Hermann-Mauguin notation). There are two principal forms in this class: the rhombohedron and the hexagonal scalenohedron.
Minerals shape this way are scalenohedral. scales Aggregate of small, flattened, overlapping crystals, as seen in fish scales. scaly Describing an aggregate of scales. scarp The steep cliff face that is formed by a slump.
Arsenic, antimony and bismuth crystallize in the hexagonal-scalenohedral class while selenium and tellurium crystallize in the trigonal-trapezoidal class. Natural crystals of all three species are rare.
Tourmaline: A complex crystalline silicate occurring usually in three-sided or six-sided prisms terminated by rhombohedral or scalenohedral planes containing aluminum, boron, and other elements.
Hexagonal (commonly rhombohedral, prismatic and scalenohedral. Sometimes massive.)
Envronment:
hypothermal veins, and hydrothermal replacements.
viewed through a clear piece of calcite appear doubled in all of their parts-a phenomenon first described by Rasmus Bartholin. A beautifully transparent variety used for optical purposes comes from Iceland, called Iceland spar. Acute scalenohedral ...
Scarlet to vermilion in color and streak, proustite forms compact masses and prismatic, rhombohedral, or scalenohedral crystals (hexagonal system) often associated with PYRARGYRITE, or dark ruby silver, in silver veins.
 See also: Crystal, Crystals, Mineral, Group, Quartz
  
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