Carlinite is a rare thallium sulfide mineral typically found as microscopic inclusions within gold-bearing sediment deposits. It is best known as a type-locality mineral from the Carlin trend in Nevada, where it was first identified through electron microprobe analysis. Due to its extreme rarity and toxicity, it is almost exclusively held in research-grade mineral collections.
Is this carlinite?
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 carlinite with a known reference. Carlinite sits at Mohs ~1, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: dark gray to black.
- 3Read the lusterHold the specimen under a strong light. Luster: bright metallic.
- 4Match the color rangeCompare against the expected color range: dark gray, black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: microscopic grains, anhedral masses.
Often confused with
Carlinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Carlinite leaves dark gray to black, Orpiment leaves pale lemon-yellow; luster reads bright metallic on Carlinite and resinous, pearly on cleavage surface on Orpiment.
How to tell apart: Streak differs, so Carlinite leaves dark gray to black, Realgar leaves red-orange to red; luster reads bright metallic on Carlinite and resinous to greasy on Realgar.
How to tell apart: Stibnite is the harder of the two (Mohs 2 vs. ~1); streak differs, so Carlinite leaves dark gray to black, Stibnite leaves lead-gray; luster reads bright metallic on Carlinite and metallic, splendent on cleavage surfaces on Stibnite.
Often found alongside carlinite
Minerals reported to co-occur with carlinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₂S
- Mohs hardness
- ~1
- Density
- 8.1 g/cm³
- Streak
- Dark gray to black
- Luster
- Bright metallic
- Transparency
- Opaque
- Crystal system
- Trigonal
- Crystal habit
- Microscopic grains, anhedral masses
- Cleavage
- {0001}, perfect, and an imperfect prismatic cleavage
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- As small grains in brecciated fragments of carbonaceous limestone, a result of epithermal mineralization
Where rockhounds find carlinite
Classic worldwide localities
- East pit of the Carlin mine (type locality), 50 km northwest of Elko, and in the Deep Post orebody, Goldstrike mine, Lynn district, Eureka Co., Nevada, USA
Field-hunting tip
Where it forms: As small grains in brecciated fragments of carbonaceous limestone, a result of epithermal mineralization. If you start seeing gold, arsenic, antimony in float, you are in the right ground. Typical habit: microscopic grains, anhedral masses. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify carlinite?+
Where is carlinite found?+
Is carlinite safe to handle?+
What rocks look like carlinite?+
What minerals are found with carlinite?+
What kind of rock does carlinite form in?+
What is carlinite used for?+
Find carlinite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
