igneous

Granite (Core Sample)

Phaneritic Felsic Igneous Rock (Granite)

Hardness: 6-7 (Mohs scale); Color: Light grey to greenish-grey; Luster: Dull to vitreous; Crystal Structure: Phaneritic (medium-grained crystalline); Primary Minerals: Quartz, Feldspar, Mica.

Hardness: 6-7 (Mohs scale)
Color: Light grey to greenish-grey
Luster: Dull to vitreous

Identified February 7, 2026More igneous →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Light grey to greenish-grey; Luster: Dull to vitreous; Crystal Structure: Phaneritic (medium-grained crystalline); Primary Minerals: Quartz, Feldspar, Mica.

Formation & geological history

Formed through the slow cooling of silica-rich magma deep within the Earth's crust (plutonic). Found in the Arabian Shield, these cores likely date back to the Proterozoic Era (approx. 500-900 million years ago).

Uses & applications

In geological engineering, these cores are used for geotechnical assessment of load-bearing capacity for construction. Industrially, granite is used for dimension stone, countertops, and aggregate.

Geological facts

This specific sample is a geotechnical drill core from a ground investigation in Makkah. Borehole cores allow geologists to 'see' the underground stratigraphy without excavating.

Field identification & locations

Identified by its crystalline interlocking texture and hardness. Found in continental shields. Collectors look for solid, un-weathered cylinders; usually obtained from construction sites or geologists.

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Fluorapatite (Ca5(PO4)3F)

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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

Magnetite

Iron(II,III) oxide (Fe3O4)

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Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

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Magnetite

Magnetite (Fe3O4)

mineral