I’ve really been fascinated with Quartz Adularia specimen lately! The aesthetic quality of the snow white and Gold-coated Adularia inclusions is absolutely stunning. This particular tabby, water-clear specimen with incredibly lustrous terminations and growth lines has a special place in my heart! Check out the macro shots I took of the rainbow inclusions and raised/indented record keeper triangles, turned out pretty cool.
The information below will give you an idea as to how this special material forms:
“Much of the world’s Gold has been produced from Quartz veins. Veins are formed when Quartz or other minerals precipitate from a cooling fluid in a planar zone of weakness known as a fault. Quartz can precipitate from several different types of fluids, one of which is responsible for low sulphidation epithermal gold-silver veins and geothermal systems such as hot springs.
The fluids are typically a mixture of groundwater and fluid emanating from molten rock at depths of around 5-10 kilometers below surface. These hot fluids are under very high pressures at those depths, and as they rise along faults to depths of about two kilometers from the surface, they begin to boil. As the fluids boil, they cool rapidly, causing the quartz to precipitate in the fault, forming the vein. Calcite and Adularia (a feldspar mineral type) also precipitate in response to boiling as well as any gold and silver present in the fluid. Eventually the rising fluids breach the surface and form a hot spring.
Recognizing that gold precipitates near the surface in these systems, the great American geologist Waldemar Lindgren coined the term epithermal in 1933, epi- meaning shallow and
-thermal referring to the heated fluid. The chemist Werner Giggenbach further subdivided epithermal gold deposits into low and high sulphidation types (illustrated right)”
