Englishite is an exceptionally rare hydrous phosphate mineral known primarily from the Clay Canyon phosphate deposits in Utah. It typically occurs as tiny, colorless to white tabular crystals or radiating sprays associated with other rare phosphates in nodules.

Hardness

Mohs

Luster

Vitreous, pearly on cleavages

Streak

White

Transparency

Transparent

mineralrare

Englishite

Hardness: ~3
Luster: Vitreous, pearly on cleavages
Streak: White
Transparency: Transparent

Is this englishite?

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 englishite with a known reference. Englishite sits at Mohs ~3, 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, pearly on cleavages.
4
Match the color range
Compare against the expected color range: colorless, white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: aggregates, friable, micaceous.

Often confused with

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

How to tell apart: Variscite is the harder of the two (Mohs 4.5 vs. ~3).

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Often found alongside englishite

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

All properties

Chemical formula: K₃Na₂Ca₁₀Al₁₅(OH)₇(PO₄)₂₁·26H₂O
Mohs hardness: ~3
Density: 2.65-2.68 g/cm³
Colors: Colorless White
Streak: White
Luster: Vitreous, pearly on cleavages
Transparency: Transparent
Crystal system: Monoclinic
Crystal habit: Aggregates, friable, micaceous
Cleavage: On {001}, perfect, micaceous
Rarity: Rare
Uses: Collector
Host rock: In variscite nodules (Little Green Monster mine, Utah, USA); in a complex granite pegmatite (Tip Top mine, South Dakota, USA)

Where rockhounds find englishite

Classic worldwide localities

Clay Canyon, Fairfield, Utah County, Utah, USA (type locality)

Field-hunting tip

Where it forms: In variscite nodules (Little Green Monster mine, Utah, USA); in a complex granite pegmatite (Tip Top mine, South Dakota, USA). If you start seeing variscite, montgomeryite, wardite in float, you are in the right ground. Typical habit: aggregates, friable, micaceous. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify englishite?+

Mohs hardness is ~3. Luster: vitreous, pearly on cleavages. The streak is white. Common colors include colorless, white.

Where is englishite found?+

Notable localities include Clay Canyon, Fairfield, Utah County, Utah, USA (type locality).

What rocks look like englishite?+

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

What minerals are found with englishite?+

Englishite commonly co-occurs with Variscite, Montgomeryite, Wardite, Millisite, Crandallite, Eosphorite–childrenite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does englishite form in?+

Where it forms: In variscite nodules (Little Green Monster mine, Utah, USA); in a complex granite pegmatite (Tip Top mine, South Dakota, USA). Working float back to the host body is the standard way to chase a fresh occurrence.

What is englishite used for?+

Englishite is used in collector.

Find englishite on the map

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