Grumiplucite is an extremely rare mercury bismuth selenide mineral first described from the Grumipluca mine in Italy. It typically occurs as microscopic inclusions within other sulfide minerals, making it a challenging and prized specimen for micromounters. Collectors should handle it with caution due to its mercury content.
Is this grumiplucite?
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 grumiplucite with a known reference. Grumiplucite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: grayish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: microscopic crystals, prismatic.
Often confused with
Grumiplucite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside grumiplucite
Minerals reported to co-occur with grumiplucite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- HgBi₂S₄
- Mohs hardness
- 1.5-2
- Density
- 7.02 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Microscopic crystals, prismatic
- Cleavage
- Perfect on {001}, near micaceous
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Very rare, in quartz-carbonate veins in mercury deposist, probably formed during retrograde metamorphism
Where rockhounds find grumiplucite
Classic worldwide localities
- Levigliani mercury mine, near Levigliani, Tuscany, Italy (type locality)
- Droždiak vein, Rudňany deposit, ~11 km southeast of Spišská Nová Ves, northern part of Gemeric Superunit, Spišsko-gemerské, Rudohorie Mts., Slovakia
Field-hunting tip
Where it forms: Very rare, in quartz-carbonate veins in mercury deposist, probably formed during retrograde metamorphism. If you start seeing cinnbar, mercurian sphalerite, mercury in float, you are in the right ground. Typical habit: microscopic crystals, prismatic. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify grumiplucite?+
Where is grumiplucite found?+
Is grumiplucite safe to handle?+
What rocks look like grumiplucite?+
What minerals are found with grumiplucite?+
What kind of rock does grumiplucite form in?+
What is grumiplucite used for?+
Find grumiplucite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
