Igneous

Granite (Weathered)

Phaneritic Felsic Igneous Rock

Hardness: 6-7 on Mohs scale; Color: Mottled gray, black, and tan/buff from iron oxidation weathering; Luster: Dull to vitreous; Structure: Phaneritic (coarse-grained) crystalline; Cleavage: None (fractures irregularly).

Hardness: 6-7 on Mohs scale
Luster: Dull to vitreous

Identified March 5, 2026More igneous →

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Physical properties

Formation & geological history

Formed through the slow cooling and crystallization of silica-rich magma deep beneath the Earth's surface (plutonic). This specimen shows signs of surface weathering over thousands of years.

Uses & applications

Primary use in construction as dimension stone, countertops, curbing, and aggregate. Also used in tombstone manufacturing and rock climbing faces.

Geological facts

Granite makes up a large portion of the Earth's continental crust. It is primarily composed of quartz, feldspar, and mica. The tan/orange tint on this specific stone is likely Limonite or Goethite staining from the oxidation of iron-bearing minerals.

Field identification & locations

Identify in the field by its 'salt and pepper' appearance and visible interlocking crystals. It is found globally in batholiths and mountain ranges. It will not react to acid and is hard enough to scratch glass.

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Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous