Feather Jasper Identification Guide

What Feather Jasper Looks Like

Feather jasper is a trade name for an opaque variety of jasper (microcrystalline quartz) marked by branching, feather- or plume-shaped patterns in contrasting colors. Typical pieces show creamy, tan, or grey bodies crossed by reddish-brown, ochre, or black feathery sprays of iron and manganese oxide. Because it is jasper, it is fully opaque, never transparent, with a dull to waxy luster on natural surfaces that brightens to a glassy polish when tumbled or cut.

• Color: earthy tan, cream, brick-red, brown, with feather/plume markings
• Luster: waxy, greasy, or dull (vitreous when polished)
• Transparency: opaque
• Form: massive (no crystals); patterns are mineral dendrites/plumes within the silica

Step-by-Step Field ID Checklist

1. Confirm it is opaque. Hold to a strong light; feather jasper transmits no light even on thin edges.
2. Look at the pattern. Genuine feather jasper shows branching, fern- or feather-like inclusions, not concentric bands.
3. Check the luster on a broken edge — waxy and smooth, with no visible grains.
4. Test hardness (see below).
5. Feel the surface — fine-grained and slick, with no sugary or sandy texture.

Key Diagnostic Tests

• Mohs hardness 6.5–7: It will scratch glass and steel easily and cannot be scratched by a steel knife. This rules out softer patterned stones like calcite or serpentine.
• Streak: White to pale grey (the iron oxides can leave faint brown only where heavily concentrated).
• Fracture: Conchoidal (curved, shell-like) with sharp edges; no cleavage.
• Acid: Inert to dilute hydrochloric acid — no fizzing (separates it from any carbonate look-alike).
• Density: ~2.6 g/cm³, the typical "light" heft of quartz.

Common Look-Alikes and How to Tell Them Apart

• Dendritic agate / moss agate: These show similar fern patterns but the host is translucent chalcedony — light passes through thin edges, whereas feather jasper stays opaque.
• Plume agate: Also translucent and often shows concentric banding around the plumes; jasper is solidly opaque and unbanded.
• Picture jasper / landscape jasper: Patterns are scenic bands and dendrites rather than discrete feathers; the diagnostic difference is the feather morphology, not the chemistry (both are jasper).
• Painted/dyed howlite: Howlite is much softer (Mohs ~3.5) and will scratch with a knife; feather jasper will not.

Where It Is Typically Found

Feather jasper, like most jaspers, forms where silica-rich fluids fill cavities or replace fine sediment, with iron and manganese oxides creating the feather inclusions. Commercial material comes largely from Madagascar, India, Indonesia, and the western United States (Oregon, Idaho, Nevada). Hunt for it in volcanic and sedimentary terrains, in stream gravels, and on old lakebed exposures where weathered nodules wash out.