Glucine is a rare calcium beryllium phosphate, typically white to yellow. It occurs in segregations in mica-fluorite greisen in illite rocks (Boevskoye deposit, Russia). It was first described from the Boevskoye phenakite-beryl deposit, 35 km southwest of Kamensk-Ural'skii, Ural Mountains, Russia.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrare

Glucine

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Semitransparent

Is this glucine?

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 glucine with a known reference. Glucine sits at Mohs 5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: white, colorless.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: concretionary, massive.

Often confused with

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

mineral

Phenakite

Mohs 7.5-8

How to tell apart: Phenakite is the harder of the two (Mohs 7.5-8 vs. 5).

How to tell apart: Beryl is the harder of the two (Mohs 7.5-8 vs. 5).

Compare →

Often found alongside glucine

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

All properties

Chemical formula: CaBe₄(PO₄)₂(OH)₄·0.5H₂O
Mohs hardness: 5
Density: 2.23-2.40 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Monoclinic
Crystal habit: Concretionary, massive
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: As segregations in mica-fluorite greisen in illite rocks (Boevskoye deposit, Russia)

Where rockhounds find glucine

Classic worldwide localities

Mt. Mica quarry, Paris, Oxford Co., Maine, USA
Boevskoye phenakite-beryl deposit, 35 km southwest of Kamensk-Ural'skii, Ural Mountains, Russia

Field-hunting tip

Where it forms: As segregations in mica-fluorite greisen in illite rocks (Boevskoye deposit, Russia). If you start seeing moraesite, fluorite, rutile in float, you are in the right ground. Typical habit: concretionary, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify glucine?+

Mohs hardness is 5. Luster: vitreous. The streak is white. Common colors include white, colorless.

Where is glucine found?+

Notable localities include Mt. Mica quarry, Paris, Oxford Co., Maine, USA; Boevskoye phenakite-beryl deposit, 35 km southwest of Kamensk-Ural'skii, Ural Mountains, Russia.

Is glucine safe to handle?+

Glucine contains beryllium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like glucine?+

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

What minerals are found with glucine?+

Glucine commonly co-occurs with Moraesite, Fluorite, Rutile, Limonite, Quartz, Mica-clay minerals. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does glucine form in?+

Where it forms: As segregations in mica-fluorite greisen in illite rocks (Boevskoye deposit, Russia). Working float back to the host body is the standard way to chase a fresh occurrence.

What is glucine used for?+

Glucine is used in collector.

Find glucine on the map

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