Euclase is a rare beryllium aluminum silicate. The chemical formula is BeAlSiO4(OH). Chemically Euclase is a nesosilicate with small amounts of iron, sodium and potassium. In its pure form it is colorless, but in rare cases euklas can be yellow, green and blue.
It has a hardness of 7.5 on the Mohs scale and a perfect cleavage plane.
Euclase crystals are usually found in granitic pegmatites and low-temperature hydrothermal deposits. Often Euclase is found as beautiful specimens which are highly sought after by collectors.
Due to the high demand for euclase specimens and its cleavage, cut stones of fine quality are very rare.
The first documented find was in the Ural mountains in Russia. Today, based on quantity, Ouro Preto in the Minas Gerais district in Brazil is the most important deposit. Beside Brazil, there are far over 20 different countries known where Euclase is found. Especially Zimbabwe and Colombia with their beautiful blue euclase are worth mentioning.
Euclase from Colombia
The first discovery of Euclase in Colombia were in the well known Emerald deposits of Gachala and Chivor. Much later in 2016 there was another found in La Marina in western Colombia. Especially noteworthy are the bluish pieces. Like Emerald the greenish blue Euclase is colored by chromium. Clean and well colored stones are incredibly rare. Especially in Asia Euclase is extremely sought after and the carat prices raised a lot.