Cat's Eye Green Tourmaline

Cat's eye green tourmaline is green tourmaline (typically elbaite, often called verdelite) that displays chatoyancy, a bright band of reflected light that glides across the stone like the slit pupil of a cat's eye. The effect appears when the gem is cut as a cabochon.

The chatoyancy is produced by countless fine, parallel tube-like inclusions or growth channels that run along the crystal's length and reflect light in a single line.

Green is one of the most common colors for cat's eye tourmaline, making it a popular and relatively affordable phenomenal gemstone.

The green color comes from iron (and sometimes chromium or vanadium) in tourmaline that crystallizes in lithium-bearing granitic pegmatites. The cat's-eye effect requires the same crystal to contain dense, parallel growth tubes or needle-like inclusions formed during growth.

These hollow channels are common in tourmaline because of its prismatic growth structure. When abundant and well aligned, they concentrate reflected light into a single band once the stone is cut en cabochon.

Brazil, Madagascar, Afghanistan, and East Africa supply much of the chatoyant green tourmaline on the market.

Look for green body color, a cabochon cut, and a single sharp band of light that moves as the stone is tilted, all combined with tourmaline's hardness of 7-7.5, vitreous luster, and strong pleochroism.

Under magnification, fine parallel tubes or needles aligned with the long axis confirm the cause of chatoyancy. The eye should be relatively sharp and centered in fine stones.

Look-alikes include cat's eye chrysoberyl (much sharper eye, higher hardness), cat's eye apatite (softer), and cat's eye quartz; tourmaline's pleochroism and inclusion pattern help separate it.

Cat's eye green tourmaline is cut as cabochons for rings, pendants, and collector gems, valued for the combination of green color and a crisp, well-centered eye. A sharp, bright band on a richly colored stone commands the highest prices.

It offers an affordable alternative to cat's eye chrysoberyl. Metaphysically, green tourmaline is linked to the heart chakra, growth, and vitality, while the cat's-eye effect is associated with protection and insight, claims that are traditional rather than scientific.