Rutilated quartz is a variety of quartz which contains acicular (needle-like) inclusions of rutile.[1] 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 star-like, and they can be sparse or dense enough to make the quartz body nearly opaque.
While otherwise inclusions often reduce the value of a crystal, rutilated quartz is valued for the quality of these inclusions.[2] [3]