Tarbuttite is a rare zinc phosphate mineral typically found in the oxidation zones of ore deposits. It is highly prized by collectors for its sharp, distinctively shaped prismatic crystals, which are most famously associated with the Broken Hill mine in Zambia.

Hardness

3.5-4

Mohs

Luster

Vitreous, pearly on cleavages

Streak

White

Transparency

Transparent to translucent

mineralrare

Tarbuttite

Hardness: 3.5-4
Luster: Vitreous, pearly on cleavages
Streak: White
Transparency: Transparent to translucent

Is this tarbuttite?

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 tarbuttite with a known reference. Tarbuttite sits at Mohs 3.5-4, 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, brown, green, white, light yellow.
5
Look at form & habit
Crystal system: triclinic. Typical habit: prismatic, striated, wheat sheaf.

Often confused with

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

Often found alongside tarbuttite

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

All properties

Chemical formula: Zn₂(PO₄)(OH)
Mohs hardness: 3.5-4
Density: 4.19 g/cm³
Colors: Colorless Brown Green White Light yellow
Streak: White
Luster: Vitreous, pearly on cleavages
Transparency: Transparent to translucent
Crystal system: Triclinic
Crystal habit: Prismatic, striated, wheat sheaf
Cleavage: On {001}, perfect
Rarity: Rare
Uses: Collector
Host rock: An uncommon secondary mineral in the oxidized zone of zinc-bearing deposits

Where rockhounds find tarbuttite

Classic worldwide localities

Kabwe (Broken Hill), Zambia
Lueca vanadium mines, Angola
Kef Semmah mine, near Sétif, Algeria
Reaphook Hill, near Blinman, Flinders Ranges, South Australia
Broken Hill, New South Wales, Australia
Hudson Bay mine, Salmo, British Columbia, Canada

Field-hunting tip

Where it forms: An uncommon secondary mineral in the oxidized zone of zinc-bearing deposits. If you start seeing hopeite, hemimorphite, smithsonite in float, you are in the right ground. Typical habit: prismatic, striated, wheat sheaf. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tarbuttite?+

Mohs hardness is 3.5-4. Luster: vitreous, pearly on cleavages. The streak is white. Common colors include colorless, brown, green, white.

Where is tarbuttite found?+

Notable localities include Kabwe (Broken Hill), Zambia; Lueca vanadium mines, Angola; Kef Semmah mine, near Sétif, Algeria; Reaphook Hill, near Blinman, Flinders Ranges, South Australia; Broken Hill, New South Wales, Australia.

Is tarbuttite safe to handle?+

Contains zinc and phosphorus; wash hands after handling and avoid ingestion or inhalation of dust.

What rocks look like tarbuttite?+

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

What minerals are found with tarbuttite?+

Tarbuttite commonly co-occurs with Hopeite, Hemimorphite, Smithsonite, Parahopeite, Hydrozincite, Scholzite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does tarbuttite form in?+

Where it forms: An uncommon secondary mineral in the oxidized zone of zinc-bearing deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is tarbuttite used for?+

Tarbuttite is used in collector.

Find tarbuttite on the map

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