Locality: Tepetate, Villa de Arriaga Municipality, San Luis Potosí, Mexico
Size: 34 mm x 18 mm x 16 mm (1.3 in. x 0.7 in. x 0.6 in.)
Weight: 8 g (0.3 oz.)
Beautiful champagne color topaz to 20 mm —relatively large for this locality— on rhyolite matrix. Partly gemmy, partly translucent. The largest crystal has hyaline opal near the termination, which fluoresces green in short wave UV light.