Mookaite Jasper
Radiolarian Chert (Chalcedony/Jasper variety) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal/Hexagonal (Microcrystalline); typically appears in massive, cryptocrystalline forms with no visible crystal faces.
Mineral Group
Silicates (Tectosilicate group, Quartz family)
Chemical Formula
SiO2 (Mainly) with Fe2O3 (Hematite) and FeO(OH) (Goethite) inclusions
Formation Process
Sedimentary/Biological; formed from the silicification of Windalia Radiolarite (the remains of microscopic sea creatures called radiolaria) in a shallow sea bed, later enriched by iron minerals.
About This Crystal
An opaque, microcrystalline variety of chalcedony. This specimen exhibits a smooth, vitreous to waxy luster and a polished, egg-like shape. Colors range from warm mustard yellow to deep brownish-red earthy tones, often showing distinct banding or mottling.
Physical Characteristics
Color: Yellow, red, maroon, tan. Streak: White. Cleavage: None. Fracture: Conchoidal to splintery. Specific Gravity: 2.6 – 2.7. Fluorescence: Generally inert.
Optical Properties
Refractive Index: 1.544 – 1.553. Birefringence: Weak. Pleochroism: None. It is singly refractive or Aggregate polarizating due to its microcrystalline structure.
Hardness & Durability
Origin Region
Mooka Creek area in the Kennedy Ranges near Gascoyne Junction, Western Australia.
Hardness & Durability
Mohs Hardness: 6.5 – 7. It is quite durable and tough due to its lack of cleavage, making it excellent for jewelry and carving.
Care & Maintenance
Wash with warm soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners if the stone has natural fractures. Stable under sunlight and does not fade easily.
Rarity & Value
Relatively common but geographically specific to Western Australia. Value is determined by color patterns and polish quality; usually affordable in the $5–$30 range for tumbled stones.
Special Characteristics
Known for its unique earthy color combinations and 'ribbon' or 'brecciated' patterns; some specimens may contain visible fossilized radiolarian structures under high magnification.
Lore & History
Historically used by Australian Aboriginal peoples as a stone for crafting tools and for its perceived connection to the Earth. In modern lore, it is considered a 'Stone of Vitality' associated with the Root and Solar Plexus chakras.