Sheldrickite is a rare carbonate mineral primarily found in the complex alkaline rocks of the Poudrette quarry at Mont Saint-Hilaire. It typically forms small, distinct rhombohedral crystals with a warm, yellowish-colorless to white hue, often associated with other rare-earth minerals.
Is this sheldrickite?
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 sheldrickite with a known reference. Sheldrickite sits at Mohs 3, 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 silky.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: trigonal. Typical habit: aggregates, blocky.
Often confused with
Sheldrickite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside sheldrickite
Minerals reported to co-occur with sheldrickite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₃(CO₃)₂F₃(H₂O)
- Mohs hardness
- 3
- Density
- 2.86 g/cm³
- Streak
- White
- Luster
- Vitreous to silky
- Transparency
- Semitransparent
- Crystal system
- Trigonal
- Crystal habit
- Aggregates, blocky
- Cleavage
- Parting on {001}, good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare late-stage hydrothermal mineral in a marble xenolith in nepheline syenite associated with an intrusive alkalic gabbro-syenite complex
Where rockhounds find sheldrickite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Where it forms: A very rare late-stage hydrothermal mineral in a marble xenolith in nepheline syenite associated with an intrusive alkalic gabbro-syenite complex. If you start seeing shortite, pectolite, microcline in float, you are in the right ground. Typical habit: aggregates, blocky. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sheldrickite?+
Where is sheldrickite found?+
What rocks look like sheldrickite?+
What minerals are found with sheldrickite?+
What kind of rock does sheldrickite form in?+
What is sheldrickite used for?+
Find sheldrickite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
