Pahasapaite is an extremely rare beryllophosphate mineral found almost exclusively in the Tip Top Mine in South Dakota. It typically forms small, attractive dodecahedral crystals and is highly prized by collectors for its unique structure and intense fluorescence under ultraviolet light.

Hardness

~4.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Pahasapaite

Hardness: ~4.5
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this pahasapaite?

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 pahasapaite with a known reference. Pahasapaite sits at Mohs ~4.5, 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, yellow green, light pink.
5
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals, crusts.

Often confused with

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

How to tell apart: Garnet is the harder of the two (Mohs 6.5-7.5 vs. ~4.5).

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Often found alongside pahasapaite

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

All properties

Chemical formula: Li₈(Ca,Li,K)₁₀.₅Be₂₄(PO₄)₂₄·38H₂O
Mohs hardness: ~4.5
Density: 2.28 g/cm³
Colors: Colorless Yellow green Light pink
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Dodecahedral crystals, crusts
Cleavage: None
Fluorescence: Bright yellow under SW UV
Rarity: Rare
Uses: Collector
Host rock: A rare late-stage mineral in seams in fractured beryl crystals, within the inner-intermediate zone of a complex granite pegmatite

Where rockhounds find pahasapaite

Classic worldwide localities

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

Field-hunting tip

Where it forms: A rare late-stage mineral in seams in fractured beryl crystals, within the inner-intermediate zone of a complex granite pegmatite. If you start seeing englishite, roscherite, eosphorite–childrenite in float, you are in the right ground. Typical habit: dodecahedral crystals, crusts. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify pahasapaite?+

Mohs hardness is ~4.5. Luster: vitreous. The streak is white. Common colors include colorless, yellow green, light pink.

Where is pahasapaite found?+

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

Is pahasapaite safe to handle?+

Pahasapaite 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 pahasapaite?+

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

What minerals are found with pahasapaite?+

Pahasapaite commonly co-occurs with Englishite, Roscherite, Eosphorite–childrenite, Tiptopite, Montgomeryite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does pahasapaite form in?+

Where it forms: A rare late-stage mineral in seams in fractured beryl crystals, within the inner-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 pahasapaite used for?+

Pahasapaite is used in collector.

Find pahasapaite on the map

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