Mineraloid
Cullet Glass (Slag)
Amorphous Silicon Dioxide (Man-made)
Hardness: 5-6 Mohs. Color: Translucent white with swirls of red and pink. Luster: Vitreous (glassy). Structure: Amorphous (non-crystalline). Cleavage: None, exhibits conchoidal fracture. Specific Gravity: ~2.4-2.8.
- Hardness
- 5-6 Mohs
- Color
- Translucent white with swirls of red and pink
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 5-6 Mohs. Color: Translucent white with swirls of red and pink. Luster: Vitreous (glassy). Structure: Amorphous (non-crystalline). Cleavage: None, exhibits conchoidal fracture. Specific Gravity: ~2.4-2.8.
Formation & geological history
Formed as a byproduct of industrial glass manufacturing or as waste glass melting in furnaces. This is not a naturally occurring geological formation but is frequently collected as a specimen.
Uses & applications
Used primarily for decorative landscaping, fish tanks, garden ornaments, and occasionally lapidary work for inexpensive jewelry.
Geological facts
While often mistaken for quartz or opal, the presence of internal air bubbles (visible in many sections) and the swirled 'taffy-like' color distribution are diagnostic of glass.
Field identification & locations
Identify by looking for conchoidal (shell-like) fractures and smooth, rounded edges on broken faces. It lacks the crystal faces found in natural minerals. Common in industrial areas or antique glass factory sites.
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