The green turquoise cabochon shown here is 23mm long. It is available to be handcrafted into a custom made ring or pendant for you. 

This stone is comprised of Kingman Turquoise which has been dyed, compressed and stabilized with bronze metal veining. It is from Arizona. You can read more about gemstone treatments here. In order to keep your stone looking good, it is recommended that you do not get it wet or expose it to sunlight for prolonged periods. Your piece can be cleaned using a soft silver polishing cloth.