Euclase is a rare form of datolite, which sometimes has the clarity to be used as a gemstone. Euclase is a silicate of beryllium and aluminum, like 
beryl, but it also contains hydrogen. The first examples of the discovery of euclase were in South America, in 1785, when the stone was first sent to Europe. The name euclase comes from the combination of two Greek words: eu, which means 'well', and klasis, which means 'breaking'. Well breaking refers to the stone's easy cleavage. Although euclase is an extremely popular stone amongst mineral collectors, it does have a tendency to chip, so very special care must be taken when cutting and polishing the stone.
Often times, the stone's fragility causes problems with its durability. Euclase's cleavage is parallel to the plane of symmetry, so the stone is most often rendered into step cut and table cuts, with the bluish-green being the most highly valued. Some euclase stones are not as valuable as they suffer from uneven color distribution. Once euclase has been cut, the stone looks like 
topaz and other types of beryl, including 
aquamarine. Euclase can be colorless to 
sapphire-blue, rose, red, pale blue-green, green, or even white. All of these various colors vary in intensity within each stone. The most attractive and highly prized color of euclase is a beautiful, pale aquamarine blue.
Euclase rates a 7.5 on the hardness scale. Its crystals are prismatic with perfect cleavage and they are transparent to translucent with a vitreous luster. Euclase occurs mostly in younger, gem-rich granite pegmatites in association with other beryllium minerals, especially beryl. It is therefore found in former beryl deposits in Sri Lanka, Zimbabwe and Brazil. Sometimes, euclase occurs as small crystals next to feldspars. Small euclase crystals can be found as eroded pebbles in rivers and streams, alongside gold. Euclase can also be found in association with 
quartz, micas, and pericline.
Euclase is found at various locations in the southeastern Brazilian state of Minas Gerais, at Alto, Ecuador; Rio Grande do Norte, northeast Brazil; Chivor, Boyaca, central Columbia; Fichtelgebirge, Bavaria, southern Germany; Yakutia, northeast Siberia, Russia; Okehampton, Devon, southwest England; and in the United States in Fairfield County, Connecticut. A beautiful blue specimen of euclase was first collected in the late 1970's from Mwame, in the Hurungwe District in northern Zimbabwe. Other important sites around the world where euclase can be found are in Mozambique, the United Kingdom, Zaire, Tanzania, Kenya, and India. Euclase is a stone that gives us peace, as it is associated with the principal of justice. It teaches us to believe that life is justice, despite appearances to the contrary.
