Man-made material (Anthropogenic 'mineraloid')
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives
Hardness: 5.5–7 (Mohs scale); Color: Translucent white/clear (frosted); Luster: Vitreous to waxy/frosted; Crystal Structure: Amorphous (none); Cleavage: Conchoidal fracture; Specific Gravity: 2.4–2.8
- Hardness
- 5
- Color
- Translucent white/clear (frosted)
- Luster
- Vitreous to waxy/frosted
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Physical properties
Hardness: 5.5–7 (Mohs scale); Color: Translucent white/clear (frosted); Luster: Vitreous to waxy/frosted; Crystal Structure: Amorphous (none); Cleavage: Conchoidal fracture; Specific Gravity: 2.4–2.8
Formation & geological history
Formed from discarded glass bottles or jars that have been physically weathered and chemically hydrated by ocean or lake water over several decades. Most sea glass is 20 to 100 years old.
Uses & applications
Primarily used in jewelry (necklaces, earrings), mosaic art, home decor, and as a popular beachcombing collectible.
Geological facts
A piece of glass must tumble in the water for at least 20 to 30 years to develop its characteristic frosted texture and rounded edges. Historically, 'Genuine' sea glass is becoming rarer as plastic replaces glass containers.
Field identification & locations
Identify in the field by its rounded, non-sharp edges and 'frosted' pitting on the surface. Found on rocky or pebbly shorelines near historical dumping sites or high shipping traffic. Authentic pieces will have tiny 'C' shaped hydration marks under magnification.
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