Hawk's Eye

Hawk's eye is a blue-grey to blue-green chatoyant quartz, closely related to the golden-brown tiger's eye. Both display a moving band of silky light, called chatoyancy, that glides across the polished surface.

Hawk's eye represents an earlier stage of the same alteration that produces tiger's eye: it retains a blue-grey color before further oxidation turns the fibers golden brown. Some stones grade between the two.

It is cut into cabochons and beads, valued for its subtle, falcon-eye sheen and smoky blue tones.

Hawk's eye forms from the fibrous blue mineral crocidolite (a form of riebeckite asbestos) that becomes replaced and infilled by quartz while preserving the original parallel fiber structure. This is the same crocidolite-to-quartz process that creates tiger's eye.

In hawk's eye, the iron in the crocidolite remains relatively unoxidized, keeping the blue-grey color. With more oxidation the iron rusts to golden brown, producing tiger's eye.

The classic source is the Northern Cape of South Africa, with additional material from Western Australia, India, and Brazil.

Look for a blue-grey to blue-green stone showing a single bright band of moving light (chatoyancy) when rotated. Hardness is 7; it scratches glass. The luster is silky to vitreous and the streak is white.

Fibers are aligned parallel, and the stone is opaque.

Look-alikes: Golden tiger's eye is the same material at a different oxidation stage; pietersite is a brecciated, swirled relative with chaotic chatoyancy. Blue dyed quartz lacks the fibrous fine sheen. Genuine hawk's eye shows a crisp, single moving light band along the fiber direction.

Hawk's eye is primarily a lapidary gemstone cut into cabochons, beads, and tumbled stones for jewelry, valued for its understated blue chatoyant glow. It is durable enough for rings, pendants, and earrings.

It has no significant industrial use, though its parent crocidolite (blue asbestos) is historically notable and should be handled cautiously only as raw fibrous material, not as the safe silicified gemstone.

Metaphysically it is associated with insight, perspective, and grounding, claims that are spiritual rather than scientific.