mineral

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to light tan/orange (iron staining); Luster: Vitreous to waxy (when water-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white to light tan/orange (iron staining)
Luster: Vitreous to waxy (when water-worn)

Identified June 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich fluids in igneous or metamorphic environments. This specific specimen is a water-worn river pebble, shaped by fluvial transport and erosion over thousands of years as it moved from its source rock.

Uses & applications

Used in glassmaking, construction aggregates, and abrasives. High-quality varieties are used in jewelry (as citrine or amethyst) and electronics (piezoelectric properties). Pebbles like this are common in landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These rounded pebbles are often called 'river stones' or 'omiyage' in certain cultures. They can survive millions of years of erosion due to their high chemical and physical stability.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel blade) and lack of cleavage. Commonly found in riverbeds, beaches, and glacial till. Look for a waxy or sugary texture and light-transmitting properties when held to light.