sedimentary

Yellow Jasper

Silicon Dioxide with Limonite (SiO2 + FeO(OH)·nH2O)

Hardness: 6.5-7 (Mohs), Color: Ochre to mustard yellow with occasional reddish streaks, Luster: Dull to waxy, Crystal Structure: Hexagonal (microcrystalline/cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.58-2.91

Hardness: 6

Identified July 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when silica-rich fluids permeate through volcanic ash or sedimentary layers. The yellow color is primarily caused by inclusions of iron oxides such as goethite or limonite. Many specimens date back to the Cretaceous or earlier periods.

Uses & applications

Used primarily as a gemstone for jewelry (cabochons), lapidary work, decorative carvings, and as a popular specimen for rock collectors and metaphysical use.

Geological facts

Jasper is an opaque variety of chalcedony. Historically, it was known as the 'Supreme Nurturer' in ancient cultures and was used by various civilizations for seals and talismans.

Field identification & locations

Identify by its characteristic mustard yellow color, opacity (light will not pass through even thin edges), and its smooth, shell-like (conchoidal) fracture surface. Common in riverbeds and desert environments globally, notably in the USA, India, and Madagascar.

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Sandstone

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