igneous or metamorphic (base stone); anthropogenic (decoration)
Pet Rock (Man-made Quartzite or Granite Cobble)
Silicon dioxide (SiO2) mixture; commonly composed of Quartz, Feldspar, and Mica
Hardness: 6-7 (Mohs scale); Color: Tan/Brown with black/pink ink highlights; Luster: Dull/Waxy; Texture: Smooth, water-worn/tumbled polish.
- Hardness
- 6-7 (Mohs scale)
- Color
- Tan/Brown with black/pink ink highlights
- Luster
- Dull/Waxy
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Physical properties
Hardness: 6-7 (Mohs scale); Color: Tan/Brown with black/pink ink highlights; Luster: Dull/Waxy; Texture: Smooth, water-worn/tumbled polish.
Formation & geological history
Formed through natural geological processes (heat/pressure or cooling magma) followed by fluvial erosion to create a rounded cobble. Subsequently modified by human hand using decorative ink.
Uses & applications
Home decor, novelty gift, paperweight, and personal sentiment. Not typically used for industrial extraction.
Geological facts
The 'Pet Rock' phenomenon peaked in 1975 when Gary Dahl sold ordinary stones as low-maintenance pets, making him a millionaire in months.
Field identification & locations
Identify by the presence of a face or human-made drawings on a rounded river rock. Often found in gardens, craft stores, or child-led collections.
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