Rutilated Quartz
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameRutilated Quartz
Chemical FormulaSiO2 (with TiO2 inclusions)
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorsbrown, smoky, reddish-brown, golden
Transparencytransparent
Type LocalityIbitiara, Bahia, Northeast Region, Brazil
Mineral GroupSilicates
Usesjewelry, collector
Associated Mineralsrutile
Rarityuncommon
Description
This specimen is a large, well-formed crystal of smoky quartz, densely packed with fine, hair-like inclusions of reddish-brown rutile needles. The rutile inclusions create a striking visual effect within the transparent quartz host.
Geological Context
Rutilated quartz forms when rutile (titanium dioxide) needles crystallize within a growing quartz crystal. This often occurs in hydrothermal veins or pegmatites, where conditions allow for the simultaneous or sequential growth of both minerals.
