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Although euclase can resemble beryl in its appearance, that is where the comparison ends. Unlike beryl, euclase contains water, has a monoclinic crystal system and a higher specific gravity. It is only occasionally that its well-formed crystals have sufficient clarity to be cut as gemstones. Crystals are commonly prismatic, can be long or short and are striated. Because of their rarity, gems with good clarity command premium prices. Most material is colorless to pale blue or pale green, but colors can range from blue to blue-green, green, yellow, white, colorless, and, rarely, purple.

Euclase Polished
Euclase Classification
Common Name Euclase
Species Euclase
Euclase Optical Properties
Transparency Transparent
Dispersion Strength: Weak Fire Value: 0.016
Refractive Index 1.652-1.671
Birefringence 0.019- 0.020
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Doubly Refractive (DR)
Fluorescence SWUV: inert to weak pale yellow
LWUV: inert to weak red
Pleochroism Trichroic, unobservable or weak, colorless, yellowish green, and blue-green
Euclase Characteristic Physical Properties
Hardness 7.5
Streak White
Specific Gravity 3.000-3.120 Typical:3.080
Toughness Poor
Inclusions Euclase can contain quartz and fluid inclusions. Red or blue plate like inclusions and dark gray metallic inclusions of bravoite are possible. Colorless stones or pale yellow stones might have blue-green color zoning.
Luster Vitreous
Fracture Conchoidal
Cleavage Perfect, in one direction, Good, in two directions
Euclase Chemistry & Crystallography
Chemical Name beryllium aluminum silicate hydroxide
Chemical Formula BeAlSiO4OH
Crystal System Monoclinic
Chemistry Classification Silicate

Euclase Colors

  • Blue Euclase Blue
  • Yellow Euclase Yellow
  • Green Euclase Green
  • Colorless Euclase Colorless
  • White Euclase White

Countries of Origin



It's clear, sparkly, and a 7-1/2 on the Mohs scale. It comes in an array of compelling colors - from blue to blue-green, green, yellow, white, colorless, and, rarely, purple. This stone is extremely rare, and it breaks easily. In fact, its name comes from the Greek words "eu and klasis" which together mean good fracture. All this makes it a great stone for collectors. Euclase can resemble beryl in its appearance, but in no other way are they related. Euclase contains water, has a monoclinic crystal system and a higher specific gravity than beryl. It is only occasionally that its well-formed crystals have enough clarity to be cut as gemstones.

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More About Euclase

In modern culture, many stones are ascribed metaphysical properties. There's no scientific evidence that stones have any powers except the power to please. Those who believe in the metaphysical call euclase the happiness stone and believe it can help them feel happy.

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.