man-made silicate (anthropogenic glass)

Sea Glass (Uranium/Vaseline Glass variant)

Silicon Dioxide (SiO2) with trace Uranium Oxide (U3O8)

AI-generated identification · may be incorrect

Hardness: 5.5-6.0 Mohs; Color: Lime green to yellow; Luster: Frosted/Vitreous; Structure: Amorphous (non-crystalline); Cleavage: Conchoidal; Specific Gravity: 2.4-2.6. Fluoresces bright neon green under UV light.

Hardness: 5
Color: Lime green to yellow
Luster: Frosted/Vitreous

Identified March 22, 2026More man-made silicate (anthropogenic glass) →

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Physical properties

Formation & geological history

Formed from discarded glassware manufactured between the late 19th century and the mid-20th century. Over decades of tumbling in salt water with abrasive sand and rocks, the edges become rounded and the surface develops a characteristic frosted hydration patina.

Uses & applications

Used in jewelry making, beach-combing collections, and artisanal mosaics. Historically, uranium was used as a coloring agent for decorative table glass and vanity items.

Geological facts

Uranium glass (often called Vaseline glass) contains about 2% uranium by weight. It is famous for its radioactive property that causes it to glow intensely green under a blacklight. Despite the uranium content, it emits very low levels of radiation and is generally considered safe for handling as a specimen.

Field identification & locations

Identify in the field by looking for a translucent, frosted greenish-yellow pebble-like object with rounded edges and pitting. Collectors often use a portable UV flashlight at night on beaches to find these specific glowing shards. Common on beaches near old coastal dump sites or historical settlements.