This group includes compact quartz containing inclusions of another mineral which determines the appearance and color.
Tiger’s Eye and Hawk Eye: The name comes from the fact that the polished cabochons show a light stripe evoking the split pupil of a tiger, the second name refers to the bird eye. Tiger’s Eye: yellow gold bronze due to oxidized iron-rich crocidolite
Hawk Eye: blue steel, dark blue to blue-green due to fine inclusions of unoxidized crocidolite. For both, shimmering reflection, rippling with curly look when acicular inclusions are wrinkled, silky texture of fiber breakage.
Cat’s Eye: it is a compact quartz, of light color, containing tremolite fibers arranged in parallel that make that cut en cabochon, it has a luminous line reminiscent of a cat’s eye.
Bull’s eye: alternating red jasper and metal oxides, rare stone.
Aventurine or aventurine quartz, name from the Italian “per avventura” meaning by chance. Known since 1700, green (due to the presence of fuchsite), reddish brown (due to flakes of hematite), golden brown, reddish fluorescent. This gem sparkles, seeming all the more “glittering ” as the lamellar inclusions are numerous and large.
Prase, or prase quartz: green, which gave it its name, due to fibers of actinolite.
Blue quartz: compact variety of quartz with inclusions of needles of blue dumortierite which gives it its color.