Acetamide is an extremely rare organic mineral found primarily in burning coal seams where it forms as a sublimation product. It typically appears as delicate colorless or white hexagonal plates and fibers, but it is notoriously unstable and sensitive to humidity.
Is this acetamide?
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 acetamide with a known reference. Acetamide sits at Mohs 1-1.5, 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: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: colorless, gray.
- 5Look at form & habitCrystal system: trigonal. Typical habit: hexagonal plates, needle-like fibers, massive.
Often confused with
Acetamide vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside acetamide
Minerals reported to co-occur with acetamide. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CH₃CONH₂
- Mohs hardness
- 1-1.5
- Density
- 1.17 g/cm³
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Hexagonal plates, needle-like fibers, massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In burning waste coal heaps, formed between 50°C and 150°C
Where rockhounds find acetamide
Classic worldwide localities
- Shamokin, near Burnside, Northumberland Co., Pennsylvania, USA
- Chervonograd, L’vov-Volyn’ coal basin, Ukraine
Field-hunting tip
Where it forms: In burning waste coal heaps, formed between 50°C and 150°C. If you start seeing sal ammoniac in float, you are in the right ground. Typical habit: hexagonal plates, needle-like fibers, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find acetamide on the map
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