Lecoqite-(Y) is an extremely rare yttrium carbonate mineral found in alkaline pegmatite environments. It typically occurs as small, colorless platy crystals or delicate radial aggregates within vugs of igneous rocks.
Is this lecoqite-(y)?
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 lecoqite-(y) with a known reference. Lecoqite-(Y) sits at Mohs 3-4, 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: silky.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy crystals, radial aggregates.
Often confused with
Lecoqite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside lecoqite-(y)
Minerals reported to co-occur with lecoqite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃Y(CO₃)₃·6H₂O
- Mohs hardness
- 3-4
- Density
- 2.358 g/cm³
- Colors
- Streak
- White
- Luster
- Silky
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Platy crystals, radial aggregates
- Cleavage
- None observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage hydrothermal mineral associated with a hyperagpaitic pegmatite
Where rockhounds find lecoqite-(y)
Classic worldwide localities
- Poudrette pegmatite dike, Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Where it forms: A late-stage hydrothermal mineral associated with a hyperagpaitic pegmatite. If you start seeing microcline, albite, natrolite in float, you are in the right ground. Typical habit: platy crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lecoqite-(y)?+
Where is lecoqite-(y) found?+
What rocks look like lecoqite-(y)?+
What minerals are found with lecoqite-(y)?+
What kind of rock does lecoqite-(y) form in?+
What is lecoqite-(y) used for?+
Find lecoqite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
