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Evaluation :
Iceland Spar (Calcite) is rated at 3 on the Moh's Scale of Hardness, and is a very
soft gemstone. Because of it's softness Calcite is best used for earrings, pendants,
brooches, or other applications where it will not be subjected to knocks / scratches.
Iceland Spar (Calcite) is found in colorless and white varieties and can exhibit
wonderful transparency.
Calcite is usually transparent to opaque and some varieties exhibit fluorescence
or phosphorescence, with specimens displaying beautiful bright colors when exposed
to UV light. In fact, some examples continue to glow with color (phosphoresce),
even after the UV source has been removed. In addition to this Calcite has a unique
property, double refraction. What this means is that when rays of light enter the
stone it is split, creating fast and slow beams of light. This causes the effect
of anything and everything being viewed through Calcite appearing twice. This unique
double refraction can also cause a rainbow effect in examples that have small crystal
fractures.
The Iceland Spar variety of Calcite is the one that best exhibits the double refraction
property.
erennially popular, and widely available, the extraordinary number of varieties
and occurrences ensures that Calcite will likely always be a popular mineral. All
Calcite examples are low to moderately priced and therefore available to all.
Common Cuts :
Calcite is most commonly fashioned into decorative ornaments and spheres, but mineral
examples are also popular amongst collectors of Calcite, of which there are many.
Gem quality Calcite can be cut
into almost any known / recognized gemstone shape,
although it is normally only faceted for collectors.
Iceland Spar (Calcite) is most commonly used in the manufacture of Nichol Prisms,
which are an integral and essential part of optical instruments and polarizing microscopes.
Routine Enhancements :
There are no known enhancements for Iceland Spar (Calcite).
Care & Cleaning :
Calcite is best cleaned
using a soft, dry cloth. Extreme heat and all acids should
be avoided as Calcite is easily affected, even by relatively weak acids, which cause
the stone to effervesce, or bubble. Calcite jewelry should be kept in a fabric-lined
box, away from other harder jewelry that could easily scratch this soft mineral.
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