Euclase is a rare beryllium aluminum silicate known for its brilliant blue or colorless, highly lustrous crystals. Collectors specifically look for its distinct, chisel-like crystal terminations and its propensity to cleave along one plane, which makes it challenging for lapidary work.

Hardness

7.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Euclase

Hardness: 7.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this euclase?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch euclase with a known reference. Euclase sits at Mohs 7.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Euclase leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Euclase typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: colorless, blue, greenish-blue, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals with distinct striations, often chisel-shaped.

Often confused with

Euclase vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside euclase

Minerals reported to co-occur with euclase. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: BeAlSiO₄(OH)
Mohs hardness: 7.5
Density: 3.1 g/cm³
Colors: Colorless Blue Greenish-blue White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals with Distinct Striations, Often Chisel-shaped
Cleavage: Perfect in One Direction
Rarity: Rare
Uses: Gemstone, Collector
Host rock: Pegmatites and Hydrothermal Veins
Typical price: $100-500 per carat for facet-grade gems, higher for rare crystals

Where rockhounds find euclase

Classic worldwide localities

Minas Gerais, Brazil
Ouro Preto, Brazil
Zagi Mountains, Pakistan
Urals, Russia
Colombian emerald mines

Field-hunting tip

Look in pegmatites and hydrothermal veins country, the host setting where euclase typically forms. If you start seeing beryl, topaz, quartz in float, you are in the right ground. Field specimens usually show a prismatic crystals with distinct striations, often chisel-shaped habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify euclase?+

Mohs hardness is 7.5. It typically shows a vitreous luster. The streak is white. Common colors include colorless, blue, greenish-blue, white.

Where is euclase found?+

Notable localities include Minas Gerais, Brazil; Ouro Preto, Brazil; Zagi Mountains, Pakistan; Urals, Russia; Colombian emerald mines.

How much is euclase worth?+

Typical asking prices fall in the range of $100-500 per carat for facet-grade gems, higher for rare crystals. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like euclase?+

Euclase is most often confused with Topaz, Blue Beryl, Kyanite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with euclase?+

Euclase commonly co-occurs with Beryl, Topaz, Quartz, Chrysoberyl, Muscovite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does euclase form in?+

Euclase typically forms in pegmatites and hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is euclase used for?+

Euclase is used in gemstone, collector.

Find euclase on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.