Cinnabar is the primary ore of mercury and is easily recognized by its distinct, vibrant scarlet-red color and high density. It typically forms in hydrothermal veins associated with volcanic activity and is frequently found as massive, earthy, or granular crusts rather than well-formed crystals. Collectors should prioritize safety, as the mineral is toxic and can release hazardous mercury vapors if heated or improperly handled.
Is this cinnabar?
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 cinnabar with a known reference. Cinnabar 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. Cinnabar leaves a scarlet streak.
- 3Read the lusterHold the specimen under a strong light. Cinnabar typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: red, brownish-red, scarlet.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, massive, granular, or earthy.
Often confused with
Cinnabar vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Cinnabar leaves scarlet, Realgar leaves orange-red; luster reads adamantine on Cinnabar and resinous on Realgar.
How to tell apart: Streak differs — Cinnabar leaves scarlet, Native Copper leaves copper-red; luster reads adamantine on Cinnabar and metallic on Native Copper.
How to tell apart: Iron Ore is the harder of the two (Mohs 5-6.5 vs. 2-2.5); streak differs — Cinnabar leaves scarlet, Iron Ore leaves reddish-brown to black; luster reads adamantine on Cinnabar and metallic to submetallic on Iron Ore.
Often found alongside cinnabar
Minerals reported to co-occur with cinnabar. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- HgS
- Mohs hardness
- 2-2.5
- Density
- 8.1-8.2 g/cm³
- Colors
- Streak
- Scarlet
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals, Massive, Granular, Or Earthy
- Cleavage
- Perfect Prismatic
- Rarity
- Uncommon
- Uses
- Collector, Pigment, Ore of Mercury
- Host rock
- Epithermal Hydrothermal Veins, Volcanic Rocks
- Typical price
- $10-150 thumbnail, $200+ cabinet specimen
Where rockhounds find cinnabar
14 mapped spotsClassic worldwide localities
- Almadén, Spain
- Idrija, Slovenia
- Tongren, China
- California, USA
- Huancavelica, Peru
Field-hunting tip
Look in epithermal hydrothermal veins, volcanic rocks country — that is the host setting where cinnabar typically forms. If you start seeing pyrite, marcasite, stibnite in float, you are in the right ground. Field specimens usually show a rhombohedral crystals, massive, granular, or earthy habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nevada, Utah, Arkansas — start trip planning there.
Common questions
How do you identify cinnabar?+
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Find cinnabar on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
