Quartz set in sterling with vintage chain

Rutilated quartz is a variety of  quartz which contains acicular (needle-like) inclusions.  It is used for gemstones. These inclusions mostly look golden, but they also can appear silver, copper red or black.

The inclusions may be distributed randomly or in bundles, which sometimes are arranged stari like and they can be sparse or dense enough to make the quartz body nearly opaque.