mineral
Blue glassy fragment among beach gravel
Likely cobalt-blue man-made glass; not a natural mineral specimen
AI-generated identification · may be incorrectVivid translucent cobalt-blue color, vitreous luster, conchoidal fracture, and no visible crystal structure; glass hardness is about 5–6 Mohs. The surrounding gravel contains mixed natural pebbles, but the blue fragment appears sharply angular and manufactured.
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Physical properties
Vivid translucent cobalt-blue color, vitreous luster, conchoidal fracture, and no visible crystal structure; glass hardness is about 5–6 Mohs. The surrounding gravel contains mixed natural pebbles, but the blue fragment appears sharply angular and manufactured.
Formation & geological history
Likely discarded or weathered bottle/container glass transported and abraded in beach or stream sediment; it has no geological age or mineral formation process. The surrounding deposit is unconsolidated mixed gravel and sand.
Uses & applications
The blue fragment has little collector value and may be beach glass; cobalt-colored glass is used for bottles, decoration, and art. Natural gravel is used for aggregate and landscaping.
Geological facts
Cobalt oxide produces the intense blue color in glass. Its smoothened edges may result from wave or stream abrasion, but the bright angular shape suggests limited transport.
Field identification & locations
Identify it by uniform saturated blue color, glassy translucence, conchoidal edges, and lack of cleavage or crystal faces; a scratch test and inspection for bubbles can support identification. Estimated value: $0–$5 for an ordinary fragment, occasionally $5–$20 if unusually large, well-rounded, or collectible.
