Where to Find Jasper: 383 Locations Mapped

The single most important field test: hold the stone to direct sunlight. If light passes through the edges, you have agate. If the stone blocks light completely — opaque through and through — you're holding jasper. Both are microcrystalline quartz (SiO₂), both fracture conchoidally, both scratch glass. Opacity is what separates them. Some stones grade between the two, and old-timers call those "jaspagate," but the translucency test handles 95% of identifications cleanly. Jasper runs 6.5 to 7 on the Mohs scale. It won't scratch with a steel knife, and it will scratch glass easily. The fracture is conchoidal to uneven — smoother on fine-grained material, rougher on coarser varieties with higher impurity content. Fresh fracture surfaces show a waxy to vitreous luster that feels slick under your thumb. The streak is always white, regardless of body color. Color in jasper comes from impurities, and there are plenty of them — up to 20% by volume. Iron oxides (hematite, goethite) produce the classic reds, browns, and yellows that most people associate with jasper. Clay minerals and celadonite contribute greens. Manganese oxides create pink and purple tones. The specific combination and distribution of these impurities is what generates named varieties. Distinguishing jasper from chert trips up beginners. Both are opaque microcrystalline quartz. The practical difference: jasper is more vividly colored, often patterned, and forms in volcanic or hydrothermal environments. Chert tends toward dull grays, tans, and browns, forms in sedimentary limestone or chalk beds, and lacks the dramatic coloring. Flint is essentially dark chert — same formation environment, finer grain, typically black or dark gray. Porcelainite causes confusion too; it's a fine-grained siliceous rock that resembles jasper but formed from the baking of shale or clay near coal seam fires, not from silica precipitation. Named varieties matter in jasper more than in almost any other mineral. Picture jasper shows landscape scenes from layered sediment compositions. Orbicular jasper contains concentric eye-like patterns formed by radial crystal growth. Brecciated jasper is angular fragments healed by later silica deposition. Bloodstone is dark green jasper flecked with red iron oxide spots — technically a jasper variety, though it has its own market. Bumblebee jasper from Indonesia isn't true jasper at all; it's a calcium carbonate stone colored by sulfur and arsenic compounds. The name stuck anyway.

Jasper is microcrystalline quartz carrying up to 20% foreign material — iron oxides, clay minerals, organic compounds, volcanic ash — which is what makes it opaque and colorful. Formation happens through two main pathways, and the pathway determines the patterns. In sedimentary environments, silica-rich groundwater percolates through existing sediments and replaces the original material molecule by molecule. Picture jasper forms this way. At Biggs Junction, Oregon, layers of volcanic ash decomposed into clay during quiet intervals between Columbia River Basalt flows during the Miocene, roughly 15 to 17 million years ago. Each layer carried different mineral compositions. When silica later replaced these sediments, it preserved the layered color variations — creating the scenic "landscapes" that make Biggs jasper famous. In volcanic environments, jasper forms when silica-rich fluids permeate tuff, rhyolite, or other volcanic deposits. Bruneau jasper in Idaho occurs in an extremely silica-rich rhyolite flow exposed along the Bruneau River canyon walls. The high silica content of the original flow provided both the source material and the matrix for jasper formation. Oregon's status as the jasper capital of the United States isn't accidental. The Columbia River Basalt Group — one of the largest continental flood basalt provinces on Earth — created the perfect geological setup: alternating basalt flows with sedimentary interbeds, extensive volcanic ash deposits, and prolonged hydrothermal activity to drive silica into solution and redeposit it as jasper.

Here is the hard truth about jasper: the exterior tells you almost nothing about what's inside. Weathered jasper surfaces oxidize to dull brown or gray crusts that hide spectacular interiors. A piece that looks like a boring river cobble might contain museum-grade scenic patterns. You have to cut to know. In stream gravels, feel for the waxy surface. Roll stones between your fingers — jasper feels distinctly smoother and slicker than the basalt and sandstone around it. Weight helps too; jasper is denser than most common stream rocks and feels heavier than expected for its size. Before committing to a full slab cut, window the stone first. Use a trim saw to cut a small flat on one end. If the exposed interior shows interesting patterns and clean color, proceed with a full cut. If it's muddy or dull, toss it in the tumbler pile. This saves diamond blades and disappointment. Some jasper varieties are surface-collectible without digging. River-tumbled picture jasper in Oregon creek gravels, float material from eroded rhyolite outcrops in Idaho, desert-varnished pieces in Arizona washes. Others — like Morrisonite and Bruneau — require extraction from host rock, which means harder tools and more effort. Know which type you're after before you pack your gear. Never trust a wet surface as the final preview. Wetting jasper reveals more than dry inspection, but the saw and polish reveal the truth. The cab test is your friend: cut it, polish one face, then decide.

Common red and brown jasper with no distinctive patterning is essentially worthless as rough — a few dollars per pound at most, and rock shops struggle to sell it. Named varieties from specific localities are where real value lives. Biggs Junction picture jasper rough runs $10 to $100 per pound depending on pattern quality. Pieces showing clear scenic landscapes — trees, mountains, horizon lines — bring the high end. Bruneau jasper rough sells for $20 to $200 per pound, with the best cream-and-brown layered material toward the top. Morrisonite is the premium domestic variety: high-quality rough has reached $250 per pound at Tucson gem shows, and clean slabs with multicolored patterning command even more. Finished cabochons multiply value dramatically. A $5 piece of rough becomes a $50 to $250 cabochon in skilled hands. Picture jasper cabochons showing recognizable scenic landscapes — a desert butte, a tree line, a mountain reflected in water — sell for premium prices because each one is essentially a tiny painting that nature made. Ocean jasper from Madagascar moves at $10 to $50 per pound rough, with orbicular pieces showing sharp eye patterns at the top. Polychrome jasper rough runs $5 to $30 per pound. The international varieties compete on aesthetics, but American named-locality jasper consistently commands higher prices per pound than comparable imported material.