Simonellite is a rare organic mineral typically found associated with carbonaceous deposits such as lignite and coal beds. It is known for its distinct bluish fluorescence under ultraviolet light and typically forms small, fragile, tabular crystals or crystalline masses.
Is this simonellite?
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 simonellite with a known reference. Simonellite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, massive, or as crusts.
Often confused with
Simonellite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Simonellite leaves white, Retgersite leaves pale green; luster reads resinous on Simonellite and vitreous on Retgersite.
How to tell apart: Luster reads resinous on Simonellite and greasy on Fichtelite.
Often found alongside simonellite
Minerals reported to co-occur with simonellite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- C₁₉H₂₄
- Mohs hardness
- 1-2
- Density
- 1.08 g/cm³
- Colors
- Streak
- White
- Luster
- Resinous
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals, massive, or as crusts
- Cleavage
- None
- Fluorescence
- Blue under UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In lignite, apparently derived from coniferous forests
Where rockhounds find simonellite
Classic worldwide localities
- A coal mine at Fognano, near Montepulciano, Tuscany, Italy
Field-hunting tip
Where it forms: In lignite, apparently derived from coniferous forests. If you start seeing sulfur, gypsum, calcite in float, you are in the right ground. Typical habit: tabular crystals, massive, or as crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify simonellite?+
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What rocks look like simonellite?+
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Find simonellite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
