Ehrleite is a very rare phosphate mineral typically found as small, thin, colorless to white tabular crystals in pegmatite cavities. It is primarily known from the Tip Top mine in South Dakota, where it occurs in association with other rare beryllium-bearing phosphates.

Hardness

~3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Ehrleite

Hardness: ~3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this ehrleite?

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 ehrleite with a known reference. Ehrleite sits at Mohs ~3.5, 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: colorless, white.
5
Look at form & habit
Crystal system: triclinic. Typical habit: tabular crystals, radiating aggregates.

Often confused with

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

mineral

Roscherite

Mohs 4.5

How to tell apart: Roscherite is the harder of the two (Mohs 4.5 vs. ~3.5); streak differs, so Ehrleite leaves white, Roscherite leaves light brown.

Often found alongside ehrleite

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

All properties

Chemical formula: Ca₂ZnBe(PO₄)₂(PO₃OH)·4H₂O
Mohs hardness: ~3.5
Density: 2.64 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Triclinic
Crystal habit: Tabular crystals, radiating aggregates
Cleavage: Parting on {001}
Rarity: Rare
Uses: Collector
Host rock: A very rare mineral with other secondary phosphates, in the outer to intermediate zone of a complex granite pegmatite

Where rockhounds find ehrleite

Classic worldwide localities

Found in the Tip Top mine, 8.5 km southwest of Custer, Custer Co., South Dakota, USA

Field-hunting tip

Where it forms: A very rare mineral with other secondary phosphates, in the outer to intermediate zone of a complex granite pegmatite. If you start seeing apatite, mitridatite, roscherite in float, you are in the right ground. Typical habit: tabular crystals, radiating aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify ehrleite?+

Mohs hardness is ~3.5. Luster: vitreous. The streak is white. Common colors include colorless, white.

Where is ehrleite found?+

Notable localities include Found in the Tip Top mine, 8.5 km southwest of Custer, Custer Co., South Dakota, USA.

Is ehrleite safe to handle?+

Ehrleite contains beryllium. Contains beryllium, which is toxic if inhaled or ingested; handle with care and avoid generating dust.

What rocks look like ehrleite?+

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

What minerals are found with ehrleite?+

Ehrleite commonly co-occurs with Apatite, Mitridatite, Roscherite, Hydroxyl-herderite, Goyazite–crandallite, Parascholzite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does ehrleite form in?+

Where it forms: A very rare mineral with other secondary phosphates, in the outer to intermediate zone of a complex granite pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is ehrleite used for?+

Ehrleite is used in collector.

Find ehrleite on the map

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