mineral

Sea Glass

Amorphous Silica (Anthropogenic glass) - SiO2

Hardness: 5.5 to 7 (Mohs scale), Color: Frosted white, light blue (in this sample), Luster: Vitreous/Frosted (dull when dry, shiny when wet), Crystal structure: Amorphous (non-crystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.4 - 2.8

Hardness: 5

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed from discarded glass products (bottles, jars, windows) that have been tumbled by waves and abrasive sand in oceans, lakes, or rivers for 20 to 100+ years. This process is known as 'hydration,' where the alkalis are leached from the surface.

Uses & applications

Commonly used in jewelry (necklaces, earrings), mosaic art, decorative home accents, and as highly sought-after items for beachcombers and specialized collectors.

Geological facts

Genuine sea glass is becoming rarer due to the increased use of plastic. Rare colors like true red, orange, and yellow often come from vintage car taillights or rare Depression-era glassware and are worth significantly more than white or green pieces.

Field identification & locations

Identify by looking for a 'frosted' surface finish with tiny C-shaped 'pitting' marks caused by the chemical reaction with salt water. Common locations include rocky shorelines or beaches near historical disposal sites. Collectors should check for rounded edges which indicate a well-tumbled, mature piece.

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