Feather Jasper

Feather Jasper is a trade name for jasper containing wispy, feather- or plume-like inclusions that spread through a paler silica matrix. The feathery figures are formed by mineral oxides, often iron or manganese, that grew in soft, branching plumes rather than the tight fractal branches of dendrites.

It is opaque microcrystalline quartz like all jasper, and its appeal lies in the delicate, drifting plumes that resemble feathers, smoke, or grasses. The look overlaps with plume agate, the difference being jasper's opacity.

Feather Jasper forms as silica-rich fluids precipitate microcrystalline quartz into host rock. Before or during silicification, iron- and manganese-bearing solutions diffuse through the gel-like silica and crystallize in soft, plume-shaped masses.

Unlike sharply branching dendrites, these plumes grow as feathery, three-dimensional sprays suspended in the silica. As the host fully hardens into jasper, the plumes are frozen in place, producing the wispy feather patterns visible when the stone is cut and polished.

Look for an opaque jasper with soft, feathery or plume-like figures in brown, red, or black drifting through a cream or tan body.

• Hardness: 6.5-7; scratches glass.
• Luster: waxy raw, vitreous polished.
• Streak: white.
• Look-alikes: plume agate has the same plumes but is translucent; dendritic jasper shows tighter fractal branching rather than soft feathers. Full opacity plus the wispy plume texture identify feather jasper.

Feather Jasper is a decorative lapidary stone cut into cabochons, slabs, and pendants that display its plume inclusions like miniature scenery. Collectors favor pieces with delicate, well-defined feathers.

Durable at near 7 Mohs, it polishes well and is reliable in jewelry. Metaphysically jaspers are associated with grounding and calm, traditional beliefs rather than scientifically demonstrated properties.