Synthetic / Composite Material

Cultured Marble (Synthetic)

Polymer-matrix composite (typically calcium carbonate in polyester resin)

Hardness: 3-4 on Mohs scale; Color: Off-white/Cream with potential marbling; Luster: Dull to matte (sub-vitreous); Structure: Amorphous/Solid cast; Cleavage: None; Specific Gravity: ~2.4

Hardness: 3-4 on Mohs scale
Color: Off-white/Cream with potential marbling
Luster: Dull to matte (sub-vitreous)

Identified March 22, 2026More synthetic / composite material →

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Physical properties

Hardness: 3-4 on Mohs scale; Color: Off-white/Cream with potential marbling; Luster: Dull to matte (sub-vitreous); Structure: Amorphous/Solid cast; Cleavage: None; Specific Gravity: ~2.4

Formation & geological history

Man-made industrial product. Created by mixing high-strength polyester resin with ground marble dust (calcium carbonate) and catalysts, then cast into a mold. Most prevalent in construction from the late 20th century to the present.

Uses & applications

Primary use is in residential construction for bathroom vanities, sinks, and shower stalls. Valued for its seamless integration of sink and countertop and its non-porous nature compared to natural stone.

Geological facts

Unlike real marble, cultured marble is chemically resistant to soaps and water but sensitive to extreme heat. It was popularized in the 1960s as a cost-effective alternative to quarried stone.

Field identification & locations

Identify in the field by checking the underside of the countertop for a cast-fiberglass or resin texture and a uniform, 'perfect' surface marbling that lacks the crystalline depth of natural stone. Common in suburban housing developments.

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