Tomichite is a very rare titanium-vanadium-arsenic mineral found primarily in specific metasomatized ultramafic rocks in Western Australia. It typically occurs as small, dark, platy crystals that resemble ilmenite or hematite, often requiring X-ray diffraction for definitive identification in the field.
Is this tomichite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch tomichite with a known reference. Tomichite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular.
Often confused with
Tomichite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads resinous on Tomichite and metallic to submetallic on Ilmenite.
How to tell apart: Streak differs, so Tomichite leaves black, Hematite leaves cherry-red or reddish brown; luster reads resinous on Tomichite and metallic or submetallic to dull on Hematite.
Often found alongside tomichite
Minerals reported to co-occur with tomichite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- V₄Ti₃AsO₁₃(OH)
- Mohs hardness
- 6
- Density
- 4.16 g/cm³
- Colors
- Streak
- Black
- Luster
- Resinous
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a specimen from a hydrothermal gold deposit (Kalgoorlie, Western Australia); in a gold deposit at the contact of felsic metavolcanic and metasedimentary rocks (Hemlo deposit, Canada)
Where rockhounds find tomichite
Classic worldwide localities
- Western Australia, from Kalgoorlie, probably from the Perseverance mine
- Hemlo gold deposit, Thunder Bay district, Ontario, Canada
Field-hunting tip
Where it forms: In a specimen from a hydrothermal gold deposit (Kalgoorlie, Western Australia); in a gold deposit at the contact of felsic metavolcanic and metasedimentary rocks (Hemlo deposit, Canada). If you start seeing vanadian muscovite, rutile, pyrite in float, you are in the right ground. Typical habit: tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tomichite?+
Where is tomichite found?+
Is tomichite safe to handle?+
What rocks look like tomichite?+
What minerals are found with tomichite?+
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Find tomichite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
