Lorandite is a rare thallium arsenic sulfosalt often found in low-temperature hydrothermal deposits. It is best known by collectors for its distinct cherry-red streak and its historical importance in solar neutrino detection experiments.
Is this lorandite?
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 lorandite with a known reference. Lorandite sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lorandite leaves a cherry-red streak.
- 3Read the lusterHold the specimen under a strong light. Lorandite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black, red internal reflections.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic or tabular crystals, massive.
Often confused with
Lorandite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lorandite leaves cherry-red, Realgar leaves orange-red; luster reads metallic on Lorandite and resinous on Realgar.
How to tell apart: Streak differs, so Lorandite leaves cherry-red, Stibnite leaves lead-gray.
How to tell apart: Streak differs, so Lorandite leaves cherry-red, Galena leaves lead-gray.
Often found alongside lorandite
Minerals reported to co-occur with lorandite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- TlAsS₂
- Mohs hardness
- 2-2.5
- Density
- 5.5 g/cm³
- Streak
- Cherry-red
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic or Tabular Crystals, Massive
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Hydrothermal Veins in Carbonate Rocks
- Typical price
- $50-500 depending on crystal quality and size
Where rockhounds find lorandite
Classic worldwide localities
- Allchar, North Macedonia
- Lengenbach, Binntal, Switzerland
- Jas Roux, France
Field-hunting tip
Look in hydrothermal veins in carbonate rocks country, the host setting where lorandite typically forms. If you start seeing realgar, orpiment, pyrite in float, you are in the right ground. Field specimens usually show a prismatic or tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lorandite?+
Where is lorandite found?+
How much is lorandite worth?+
Is lorandite safe to handle?+
What rocks look like lorandite?+
What minerals are found with lorandite?+
What kind of rock does lorandite form in?+
What is lorandite used for?+
Find lorandite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
