mineral

Milk Quartz (White) and Yellow Aventurine (Yellow)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Opaque white and translucent yellow/orange, Luster: Vitreous to waxy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal solutions cooling within veins or volcanic cavities. Predominantly found in metamorphic or igneous rock environments across various geological ages from Precambrian to Cenozoic.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and decorative carvings. Industrial uses include glassmaking, abrasives, and as a source of silica. Also popular in metaphysical and crystalline healing circles.

Geological facts

Milk quartz (the white specimen) gets its cloudy appearance from tiny fluid inclusions trapped during the crystal's growth. Yellow aventurine belongs to the quartz family but often contains mica inclusions that can give it a shimmering effect known as 'aventurescence'.

Field identification & locations

Identify in the field by their inability to be scratched by a steel knife (H=5.5) and their distinct waxy-to-glassy luster. Commonly found in riverbeds, mine tailings, or mountain outcrops globally (Brazil, India, Russia, USA). Collectors should look for vibrancy of color and lack of internal cracks.

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Arenite (SiO2 based)

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Banded Gneiss (River Rock/Pebble)

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