Rock Identifier
Polished Yellow Jaspar (Chalcedony / Quartz (SiO2 with Iron Oxides)) — sedimentary
sedimentary

Polished Yellow Jaspar

Chalcedony / Quartz (SiO2 with Iron Oxides)

Hardness: 6.5-7 Mohs. Color: Yellowish-brown, ochre, mustard yellow with reddish or brownish undertones. Luster: Waxy to vitreous. Crystal Structure: Microcrystalline/Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.6.

Hardness
6
Luster
Waxy to vitreous
Identified More sedimentary
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Physical properties

Hardness: 6.5-7 Mohs. Color: Yellowish-brown, ochre, mustard yellow with reddish or brownish undertones. Luster: Waxy to vitreous. Crystal Structure: Microcrystalline/Cryptocrystalline. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.6.

Formation & geological history

Formed through the deposition of silica-rich fluids within sedimentary or altered volcanic rocks, often infused with iron hydroxide minerals (such as goethite or limonite) that impart the rich yellow-brown color.

Uses & applications

Used primarily in lapidary arts, jewelry (cabochons, pendants), decorative carved items, palm stones, and for ornamental display.

Geological facts

Yellow jasper has been utilized by humans since antiquity for seals, amulets, and stone tools. Its color is due to microscopic inclusions of goethite and limonite embedded within the quartz matrix.

Field identification & locations

Identified by its opacity, hardness (will scratch steel and glass), waxy polish, and earthy yellow to brownish hue. Common worldwide, particularly in the western USA, Madagascar, South Africa, and Brazil.