Ammolite is found only in Canada. It is an organic gemstone with optical properties that causes it to flash iridescent colors. It is made of the fossilized shells and the same mineral contained in pearls, called nacre. The click-in hoop earring adds a good look and is very secure. Fabricated in 14KY, 18KY, and 22KY gold, they measure 7mm x 20mm or about 3/8″ x 3/4″. Hand crafted in my Harbor Springs, MI studio. One of a kind originals.