igneous
Granite Pebble (Porphyritic or Pink Granite)
Granite (felsic plutonic rock comprising Quartz, Potassium Feldspar, Plagioclase, and Biotite/Amphibole)
Hardness: 6-7 on Mohs scale. Color: Mottled pink, grey, white, and dark specks. Luster: Dull to vitreous on fresh surfaces. Texture: Phaneritic to porphyritic with rounded, water-worn outer edges. Cleavage: Poor/none in whole rock (individual feldspars show cleavage). Specific Gravity: ~2.63-2.75.
- Hardness
- 6-7 on Mohs scale
- Color
- Mottled pink, grey, white, and dark specks
- Luster
- Dull to vitreous on fresh surfaces
Identified More igneous →
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Physical properties
Hardness: 6-7 on Mohs scale. Color: Mottled pink, grey, white, and dark specks. Luster: Dull to vitreous on fresh surfaces. Texture: Phaneritic to porphyritic with rounded, water-worn outer edges. Cleavage: Poor/none in whole rock (individual feldspars show cleavage). Specific Gravity: ~2.63-2.75.
Formation & geological history
Formed deep beneath the Earth's surface through the slow cooling and crystallization of felsic magma chamber bodies (plutons). The rounded pebble shape is the result of mechanical weathering, erosion, and transport by stream, river, or glacial activity.
Uses & applications
Crushed stone for road construction, aggregate in concrete, dimension stone for countertops and monuments, decorative landscaping gravel, and tumbling material.
Geological facts
Granite makes up the majority of Earth's continental crust. The pink hue seen in this specimen comes from orthoclase (potassium feldspar), while the quartz provides hard grey/clear domains.
Field identification & locations
Easily identified by its speckled 'salt-and-pepper' plus pink appearance, interlocking crystalline grain structure, and high hardness (scratches glass). Commonly found along riverbeds, beaches, and glacial till deposits worldwide.
