Malachite after Cuprite – Chessy lesmines, Rhone, France
 
Magnificently crystalized pseudomorphoses from malachite after cuprite with skeletonized surfaces. Crystals from the classic Chessy site in France are extremely rare and sought after as no new material is being recovered.
These crystals are mostly transformed into copper carbonates.
In part, however, only superficially. A small, unconverted core of cuprite can also be found in the malachite. And a few are completely in malachite
transformed pseudomorphoses.
The malachite forming the pseudomorphoses is never needle-like. It has more of a porcelain-like appearance.
The most common habit is the octahedron, sometimes by indenting the face
skeletal.
However, the rhombic dodecahedron with completely smooth surfaces can also be found.
Some rhombic dodecahedral crystals are elongated along a threefold axis and form
so pseudotrigonal crystals.
Today pseudomorphoses from malachite to cuprite are hardly in Chessy, but rather
found in old collections.