Turneaureite is a rare arsenic-bearing mineral belonging to the apatite supergroup, primarily found in metamorphosed manganese deposits. It typically forms as small, prismatic, or anhedral crystals and is highly prized by advanced mineral collectors for its scarcity and specific geological occurrence.

Hardness

Mohs

Luster

Vitreous to slightly greasy

Streak

White

Transparency

Translucent

mineralrareApatite Supergroup family

Turneaureite

Hardness: 5
Luster: Vitreous to slightly greasy
Streak: White
Transparency: Translucent

Is this turneaureite?

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 turneaureite with a known reference. Turneaureite 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 to slightly greasy.
4
Match the color range
Compare against the expected color range: colorless, gray white.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: prismatic crystals, anhedral grains.

Often confused with

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

How to tell apart: Turneaureite is noticeably harder (Mohs 5 vs. 3.5-4); luster reads vitreous to slightly greasy on Turneaureite and resinous to subadamantine on Mimetite.

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Often found alongside turneaureite

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

All properties

Chemical formula: Ca₅(AsO₄)₃Cl
Mohs hardness: 5
Density: 3.60 g/cm³
Colors: Colorless Gray white
Streak: White
Luster: Vitreous to slightly greasy
Transparency: Translucent
Crystal system: Hexagonal
Crystal habit: Prismatic crystals, anhedral grains
Cleavage: None
Fluorescence: Bright orange under SW UV
Rarity: Rare
Uses: Collector
Host rock: A rare component of manganiferous ores in high-grade marbles

Where rockhounds find turneaureite

Classic worldwide localities

Franklin, Sussex Co., New Jersey and in the Balmat #4 mine, Fowler, St. Lawrence Co., New York, USA
Brattfors mine, Nordmark, (Långban), Värmland, Sweden

Field-hunting tip

Where it forms: A rare component of manganiferous ores in high-grade marbles. If you start seeing andradite, magnetite, calcite in float, you are in the right ground. Typical habit: prismatic crystals, anhedral grains. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify turneaureite?+

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

Where is turneaureite found?+

Notable localities include Franklin, Sussex Co., New Jersey and in the Balmat #4 mine, Fowler, St. Lawrence Co., New York, USA; Brattfors mine, Nordmark, (Långban), Värmland, Sweden.

Is turneaureite safe to handle?+

Turneaureite contains arsenic and calls for real care. Contains arsenic, a toxic element; wash hands thoroughly after handling specimens and avoid inhaling dust or powder.

What rocks look like turneaureite?+

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

What minerals are found with turneaureite?+

Turneaureite commonly co-occurs with Andradite, Magnetite, Calcite, Manganoan calcite, Donpeacorite, Tirodite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does turneaureite form in?+

Where it forms: A rare component of manganiferous ores in high-grade marbles. Working float back to the host body is the standard way to chase a fresh occurrence.

What is turneaureite used for?+

Turneaureite is used in collector.

Find turneaureite on the map

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