Routhierite is a very rare thallium-mercury sulfosalt mineral primarily identified in specific hydrothermal deposits. It is typically found as small, deep red to black grains associated with other rare thallium minerals and is highly sought after by advanced mineral collectors.
Is this routhierite?
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 routhierite with a known reference. Routhierite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: red-brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: violet red, black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: anhedral grains.
Often confused with
Routhierite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Routhierite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs, so Routhierite leaves red-brown, Realgar leaves red-orange to red; luster reads metallic on Routhierite and resinous to greasy on Realgar.
How to tell apart: Routhierite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs, so Routhierite leaves red-brown, Cinnabar leaves scarlet; luster reads metallic on Routhierite and adamantine, inclining to metallic when dark; dull in friable material on Cinnabar.
Often found alongside routhierite
Minerals reported to co-occur with routhierite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- TlCuHg₂As₂S₆
- Mohs hardness
- 3.5
- Density
- 5.83 g/cm³
- Colors
- Violet redBlack
- Streak
- Red-brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Anhedral grains
- Cleavage
- Two perpendicular
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In hydrothermal deposits in dolostone (Jas Roux, France)
Where rockhounds find routhierite
Classic worldwide localities
- Jas Roux deposit, 10 km east of Chapelle-en-Valgaudemar, Hautes-Alpes, France (type locality)
- Vorontsovskoye gold deposit, Serov district, Northern Ural Mountains, Russia
- Hemlo gold deposit, Thunder Bay district, Ontario, Canada
Field-hunting tip
Where it forms: In hydrothermal deposits in dolostone (Jas Roux, France). If you start seeing realgar, stibnite, pierrotite in float, you are in the right ground. Typical habit: anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
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What rocks look like routhierite?+
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Find routhierite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
