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Pyrope
Magnesium-rich member of the pyrope-almandine
series The name comes from the Green pyropos, meani"fiery,
and is therefore similar to the Latin name carbi, culus(small
coal or ember), attributed to all red transpare stones. Its
red color, sometimes very bright, is due to small quantities
of chrome in the crystal structure.
Appearance Usually bright red, pyrope can
be a much less attractive brick or dark red. It can be perfectly
transparent, but this feature is less visible in dark specimens
is either made into fairly convex cabochons, like almandine
garnet, or faceted, with an oval or round mixed cut or, mc
rarely, a step cut. The faceted gems have good lust, rather
less obvious in cabochons. The most valuable types are, of
course, the transparent ones with the brightest r color. Pyrope
is relatively common, although less so the almandine. Very
large stones, up to several hundred carats, have been found;
but these are rare and are four in museums and famous collections.
Distinctive features Pyrope is singly refractive,
but. sometimes displays anomalous patches of birefringence
and has a luster comparable to that of ruby and spinel. It
is distinguished from the former by a lack of pleochroism
an the fact that it does not turn bright red in strong light;
but can only be distinguished from the latter by measuring
it physical characteristics. These are, however, somewhere
variable, as iron is inevitably present, due to its isomorph
relationship with almandine. It is called pyrope when the
density is between 3.65 and 3.87 g/cm3 and the refractim index
is between 1.730 and 1.751. (Stones with high( densities and
refractive indices are called pyrope-almandine and then almandine.)
The hardness is 7 or a little more.
Occurrence In the latter half of the nineteenth
century. most pyrope came from Bohemia, where it is still
four today. The main sources nowadays, however, are South
Africa, Zimbabwe, Tanzania, the United States, Mexico Brazil,
Argentina, and Australia.
Value It is of quite low value as secondary
gems g probably due to its abundance. The darkest specimen
- which are the most common, are worth very little. While
even in early times pyrope could be distinguished fr ruby
because of its relative softness, it was more highly valued
then than it is today, probably because of its color.
Simulants and synthetics Formerly, when it
was mow highly prized, pyrope was imitated by glass, which
can loc - very similar, but does not have the same hardness.
It is n produced synthetically.
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