Rock Crystal
Oh la la! This cluster of rock crystal (> 4.5 in.) comes from the La Gardette
mine,
overlooking the village of Bourg d'Oisans. The mine was formerly
a poor gold mine.
The most beautiful quartz that I have ever laid eyes on comes from here
- long graceful fingers of smooth, perfectly transparent prisms of pure SiO2!
These crystals are naturally coated with limonite, but removal reveals these
unparalleled specimens. They are found in crevices between the layers of
precambrian gneiss. Since prehistoric times, man has sought and collected
from this surface deposit. Now, most new finds must be excavated by
following the fissures back through the mountain.
It is very rare and expensive to find someone willing to sell these,
making it difficult to obtain high quality pieces.
However, beautiful and large examples may be seen in mineral museums across
Europe.
I bought this at the Bourg d'Oisan Show 1994.