Reederite-(Y) is an exceptionally rare carbonate mineral primarily found in the complex alkaline rocks of Mont Saint-Hilaire. It is best identified by its distinct hexagonal tabular habit and characteristic bright yellow fluorescence under short-wave ultraviolet light.
Is this reederite-(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 reederite-(y) with a known reference. Reederite-(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. Reederite-(Y) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Reederite-(Y) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-brown, brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: tabular crystals.
Often confused with
Reederite-(Y) vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside reederite-(y)
Minerals reported to co-occur with reederite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₅Y₃(CO₃)₈(SO₄)₂F
- Mohs hardness
- 3.5
- Density
- 2.91 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect On {001}
- Fluorescence
- Bright Yellow Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks
Where rockhounds find reederite-(y)
Classic worldwide localities
- Mont Saint-Hilaire, Canada
Field-hunting tip
Look in alkaline igneous rocks country, the host setting where reederite-(y) typically forms. If you start seeing aegirine, microcline, sodalite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify reederite-(y)?+
Where is reederite-(y) found?+
What rocks look like reederite-(y)?+
What minerals are found with reederite-(y)?+
What kind of rock does reederite-(y) form in?+
What is reederite-(y) used for?+
Find reederite-(y) on the map
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