mineraloid / anthropogenic (man-made origin)

Green Sea Glass

Amorphous Silica (man-made glass), SiO2 + additive metal oxides

Hardness: 5.5-6.0 Mohs; Color: Pale green (frosted); Luster: Dull/waxy due to hydration surface; Crystal Structure: Amorphous (non-crystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.4-2.8

Hardness: 5
Color: Pale green (frosted)
Luster: Dull/waxy due to hydration surface

Identified March 22, 2026More mineraloid / anthropogenic (man-made origin) →

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Physical properties

Formation & geological history

Formed from discarded glass bottles or jars that have been physically and chemically weathered by salt water and sand over several decades (typically 20-50 years).

Uses & applications

Used in artisanal jewelry, mosaic art, beach decor, and as a popular focus for beachcombing hobbyists.

Geological facts

The frosted appearance is caused by the leaching of glass components by salt water, a process called 'hydration' which creates tiny ‘C’ shaped pits on the surface. Pale green is one of the most common colors because it often originates from soda-lime glass used in beverage bottles.

Field identification & locations

Identify by its frosted, non-shiny surface and rounded edges found on shorelines. Common in coastal areas near old towns or shipping lanes. Collectors look for 'pitting' to ensure it is genuine sea glass rather than rock-tumbled glass.

Other mineraloid / anthropogenic (man-made origin) specimens

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Green Slag

Anthropogenic Silicate Glass

Mineraloid (Industrial byproduct)

Slag

Anthropogenic glassy silicate

Mineral-like byproduct

Slag Glass

Anthropogenic Amorphous Silicon Dioxide

mineral

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Byproduct)

mineraloid

Ceramic or Polished Stone Heart (Anthropogenic Material)

Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)

Synthetic/Anthropogenic Mineraloid

Man-made Slag (Industrial Byproduct)

Anthropogenic Glassy Residue

not a natural rock