These are A grade, 30 x 22mm Green Opal oval domed cabochons. The height is 8-9mm. Look closely and you will notice that these cabochons have wonderful natural black moss like inclusions that just add to the beauty of the stones. This green color is a hard one to find, but we have it for you. Peruvian Opal is actually formed because of water that gets trapped within quartz. So, it has a natural beauty that is very attractive. Peruvian opal is said to stimulate creativity and helps ideas flow more freely. It also helps us face the future. If you are looking to improve your psychic ability, it will do that too! Have any old wounds? Well, Peruvian Opal is also known to release the trauma of old wounds. And, to top it off, this stone also aids restful sleep.