Milky
Quartz
VARIETY INFORMATION:
- VARIETY OF: Quartz , SiO2
, Silicon Dioxide.
- USES: Ornamental stone.
- COLOR: various shades of white, usually milky.
- INDEX OF REFRACTION: 1.544-1.553
- BIREFRINGENCE: 0.009
- HARDNESS: 7
- CLEAVAGE: none
- CRYSTAL SYSTEM: trigonal
Milky Quartz is any quartz crystal or cluster that is white
in color and cloudy. The cloudy white character of the crystals is what lead to
the variety name, milky. The cloudiness of milky quartz comes from microscopic
inclusions of fluids that have been encased in the crystal from the time the
crystal first grew. From a cynical point of view the inclusions have ruined the
crystal from being used for the many purposes that quartz crystals are tasked to
do (e.g. gemstones or optic purposes). However, milky quartz is used in many
fine ornamental carvings and the fluid inclusions can give milky quartz a
attractive greasy luster unlike the other varieties of quartz.
Milky quartz is often responsible for the cloudy phantoms
inside of otherwise clear rock quartz, amethyst, citrine or smoky quartz. The
milky quartz may have formed at an early stage of the crystal's growth and a
later stage of clear quartz growth covered the milky quartz. The effect results
in seemingly a crystal within a crystal and the interior crystal may have a
ghostly look, hence the name phantom. The milky quartz-amethyst phantom
combination results in an ornamental stone called chevron amethyst. The
bands of amethyst and milky quartz make thin well defined chevrons of purple and
white that are attractive as polished stones and in ornamental carvings.
Milky quartz is occasionally associated with
gold in hydrothermal veins. Prospectors searching for gold laden ore, look for
outcrops of milky white quartz veins. Many of the most beautiful gold specimens
are the ones that have the lacy gold extruding from the pure white milky quartz.
Other attractive associations with milky quartz include those with rhodochrosite
(pictured above), fluorite, calcite, galena, pyrite, elbaite, micas, and many
others.
Serendipity
Ranch Gem Mine