Characteristics of Euclase:

Chemical Name: Beryllium silicate

Formula: BeAlSiO₄(OH)

Colors: Colorless, white, blue, green

Structure: Monoclinic

Hardness: 7.5

Specific Gravity: 3

Refractive Index: 1.65-1.67

Lustre: Vitreous

Streak: Colorless

Locations: Brazil, USA

What is Euclase? 

Euclase is beryllium aluminum hydroxide silicate. It is generally white or colorless but can also be pale green or pale to deep blue – a color for which it is particularly noted. It forms grooved prisms, often with complex and faces, and can also be found in masses and fibers. In faceted gems, pale to rich aquamarine is favorite, but other colors are also cut. it is relatively uncommon in gem material, and is principally cut for collectors. Euclase takes its names from the Greek eu, “good”, and classis “facture”, in reference to the way in which it breaks in perfect planes.