Got a photo? Identify rocks instantly with the Rockby app
Open the appDescription
Picture Jasper is a variety of opaque, microcrystalline quartz (chalcedony) characterized by its distinctive patterns that resemble landscapes, scenes, or abstract imagery. These patterns are formed by the inclusion of various mineral impurities, predominantly iron oxides, which impart earthy colors such as browns, tans, reds, and blacks. The silica matrix provides the hardness and durability, while the impurities create the visual appeal. It is a dense, fine-grained material.
How to Identify
- Color
- Earthy tones, predominantly browns, tans, creams, reds, and blacks, often in contrasting layers or dendritic patterns.
- Luster
- Dull to waxy, sometimes sub-vitreous on freshly broken surfaces.
- Texture
- Smooth, fine-grained, and dense. Opaque.
- Crystal Form
- Massive, cryptocrystalline (microcrystalline aggregates). Individual crystals are not visible to the naked eye.
- Cleavage
- None. Exhibits a conchoidal to sub-conchoidal fracture.
- Geological Environment
- Found in a variety of geological settings, including volcanic flows, hydrothermal veins, and sedimentary deposits. It often forms in areas where silica-rich waters percolate through existing rocks, depositing chalcedony and incorporating mineral impurities.
Key Facts
- Hardness: 6.5 - 7 on the Mohs scale
- Specific Gravity: 2.58 - 2.91
- Crystal System: Trigonal (cryptocrystalline aggregates)
- Color: Brown, tan, cream, red, black, often in variegated patterns.
- Luster: Dull to waxy, sometimes sub-vitreous.
- Transparency: Opaque.
- Fracture: Conchoidal to sub-conchoidal.
- Cleavage: None.
- Composition: SiO2 (silicon dioxide) with various iron oxides (Fe2O3, FeO(OH)·nH2O), manganese oxides, and clay minerals as impurities.
Quick Check
- Color: Earthy browns, tans, reds, blacks in scenic patterns.
- Luster: Dull to waxy.
- Streak: White.
Physical Characteristics
- Crystal Habit: Massive, cryptocrystalline aggregates; individual crystals are microscopic.
- Cleavage Type: None.
- Fracture Type: Conchoidal to sub-conchoidal, splintery.
- Tenacity: Brittle.
- Luster Type: Dull to waxy, sometimes sub-vitreous.
Formation
Picture Jasper forms as a result of the precipitation of silica-rich fluids, often in volcanic or sedimentary environments. Microscopic quartz crystals (chalcedony) grow in a fibrous or granular habit, incorporating various mineral impurities, primarily iron oxides (hematite, goethite, limonite), manganese oxides, and clay minerals. These impurities are deposited in layers or dendritic patterns, creating the characteristic 'pictures' or 'landscapes' within the stone. The patterns are often formed by rhythmic precipitation or by the infilling of fractures and voids.
Usage
Primarily used as an ornamental stone, for lapidary purposes (cabochons, spheres, carvings), and in jewelry. Its unique patterns make it highly sought after by collectors and artisans. It is also used in decorative architectural applications.
Age Distribution
Varies widely depending on the specific geological formation, ranging from Precambrian to Cenozoic.
Where to Find
Oregon, USA
Known for its high-quality Picture Jasper, particularly from the Owyhee Mountains, which often features intricate landscape-like patterns.
Idaho, USA
Various localities produce Picture Jasper, often with distinct color palettes and patterns.
Australia
Several regions yield Picture Jasper, sometimes with unique red and brown hues.
Africa (e.g., Madagascar, South Africa)
Sources of various types of jasper, including those with scenic patterns.
Finding Tips
Look for Sedimentary and Volcanic Environments
Picture Jasper is often found in areas with past volcanic activity or in sedimentary beds where silica-rich fluids have been active. Look for outcrops of chert, agate, or other chalcedony varieties.
Examine Riverbeds and Alluvial Deposits
Water erosion can transport and concentrate jasper nodules and fragments in riverbeds, gravel bars, and alluvial fans. Look for rounded, dense stones with earthy colors.
Identify Characteristic Patterns
The most distinguishing feature is the 'picture' or 'landscape' patterns. Look for contrasting colors and layered or dendritic formations within the stone.
Check for Hardness
Jasper is relatively hard (Mohs 6.5-7). It will scratch glass and will not be easily scratched by a steel knife.
Similar Rocks
Ocean Jasper
Chalcedony with various mineral inclusions
Also known as: Orbicular Jasper
Mookaite Jasper
Silicified radiolarian chert
Also known as: Mookite
Polychrome Jasper
Chalcedony with various mineral inclusions
Also known as: Desert Jasper
Dendritic Agate
Chalcedony with manganese or iron oxide dendrites
Also known as: Tree Agate
Scientific Classification
- Mineral Class
- Silicates (Tectosilicates)
- Group
- Quartz Group (Chalcedony variety)
- Crystal System
- Trigonal (for individual quartz crystals, but massive for chalcedony)
- Chemical Formula
- SiO2 (with various impurities)
- Composition
- Silicon dioxide with inclusions of iron oxides, manganese oxides, and clay minerals.
Explore Picture Jasper
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.