igneous
Granite / Diorite Xenolith or Contact
Felsic-Mafic Intrusive Igneous Rock
Mohs hardness of 6-7, white and black coloration, vitreous to dull luster, phaneritic crystal structure with visible interlocking grains, specific gravity around 2.6-2.8.
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Physical properties
Mohs hardness of 6-7, white and black coloration, vitreous to dull luster, phaneritic crystal structure with visible interlocking grains, specific gravity around 2.6-2.8.
Formation & geological history
Formed by the slow cooling of magma beneath the Earth's surface. This specimen shows a sharp contact or xenolith between a lighter felsic component (granitic) and a darker mafic component (diorite/gabbro).
Uses & applications
Used in construction, architectural facings, monuments, countertops, and as decorative landscape gravel or specimens for education.
Geological facts
Granite is the most common intrusive rock in the Earth's continental crust. Specimens showing distinct compositional boundaries or xenoliths are particularly prized by geology students and collectors for demonstrating magmatic processes.
Field identification & locations
Easily identified by the contrasting light and dark speckled mineral grains. Found worldwide in major mountain ranges, shields, and cratons.
