igneous
Tumbled Granite
Granite (Felsic intrusive igneous rock)
Hardness: 6-7 Mohs; Color: Mottled gray, black, and pinkish-brown; Luster: Vitreous to dull (polished in this specimen); Structure: Phaneritic (granular); Specific Gravity: 2.63-2.75
- Hardness
- 6-7 Mohs
- Color
- Mottled gray, black, and pinkish-brown
- Luster
- Vitreous to dull (polished in this specimen)
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Physical properties
Hardness: 6-7 Mohs; Color: Mottled gray, black, and pinkish-brown; Luster: Vitreous to dull (polished in this specimen); Structure: Phaneritic (granular); Specific Gravity: 2.63-2.75
Formation & geological history
Formed from the slow cooling of silica-rich magma deep underground. These specimens are likely derived from glacial or river erosion and then mechanically tumbled to a smooth finish.
Uses & applications
Decorative landscaping, jewelry making (cabochons), talismans (worry stones), and construction (cladding/flooring in larger scales).
Geological facts
Granite makes up a large portion of the Earth's continental crust. Its name comes from the Latin 'granum', meaning a grain, in reference to its coarse-grained structure.
Field identification & locations
Identify in the field by its speckled 'salt and pepper' appearance and visible interlocking crystals of quartz, feldspar, and mica. Found globally in mountainous regions and riverbeds.
