Cetineite is a rare antimony sulfosalt typically found as delicate, vibrant red acicular needles. It is most famous for its occurrence in the antimony mines of Tuscany, where it forms beautiful radiating sprays within cavities of altered host rock.
Is this cetineite?
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 cetineite with a known reference. Cetineite 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: orange.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: yellow orange, orange red.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular.
Often confused with
Cetineite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Cetineite is noticeably harder (Mohs 3.5 vs. 1-1.5); streak differs, so Cetineite leaves orange, Kermesite leaves brownish red; luster reads resinous on Cetineite and adamantine to semimetallic on Kermesite.
How to tell apart: Cetineite is noticeably harder (Mohs 3.5 vs. 2); streak differs, so Cetineite leaves orange, Stibnite leaves lead-gray; luster reads resinous on Cetineite and metallic, splendent on cleavage surfaces on Stibnite.
Often found alongside cetineite
Minerals reported to co-occur with cetineite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaK₅Sb₁₄S₆O₁₈·6H₂O
- Mohs hardness
- 3.5
- Density
- 4.21 g/cm³
- Colors
- Streak
- Orange
- Luster
- Resinous
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular
- Cleavage
- On {1010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From an antimony deposit in highly silicified evaporites, on ore which has been roasted, then long weathered
Where rockhounds find cetineite
Classic worldwide localities
- Cetine mine, 20 km southwest of Siena, Tuscany, Italy
Field-hunting tip
Where it forms: From an antimony deposit in highly silicified evaporites, on ore which has been roasted, then long weathered. If you start seeing mopungite, sénarmontite in float, you are in the right ground. Typical habit: acicular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cetineite?+
Where is cetineite found?+
Is cetineite safe to handle?+
What rocks look like cetineite?+
What minerals are found with cetineite?+
What kind of rock does cetineite form in?+
What is cetineite used for?+
Find cetineite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
