Moydite-(Y) is an exceptionally rare yttrium borate mineral typically found as small, platy, or radiating crystals in pegmatites. It is primarily identified by its characteristic association with rare-earth element minerals and requires micro-analysis for definitive confirmation by most collectors.
Is this moydite-(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 moydite-(y) with a known reference. Moydite-(Y) sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Moydite-(Y) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Moydite-(Y) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, yellow, tan.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: platy crystals, radial aggregates.
Often confused with
Moydite-(Y) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside moydite-(y)
Minerals reported to co-occur with moydite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Y(B(OH)₄)CO₃
- Mohs hardness
- 3.5
- Density
- 4.26 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Platy Crystals, Radial Aggregates
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $100-500 for high-quality micro specimens
Where rockhounds find moydite-(y)
Classic worldwide localities
- Evans-Lou mine, Quebec, Canada
Field-hunting tip
Look in granite pegmatites country — that is the host setting where moydite-(y) typically forms. If you start seeing fluorite, microcline, quartz in float, you are in the right ground. Field specimens usually show a platy crystals, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify moydite-(y)?+
Where is moydite-(y) found?+
How much is moydite-(y) worth?+
What rocks look like moydite-(y)?+
What minerals are found with moydite-(y)?+
What kind of rock does moydite-(y) form in?+
What is moydite-(y) used for?+
Find moydite-(y) on the map
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