Ashcroftine-(Y) is a rare potassium-sodium-yttrium silicate mineral known for its striking pink, radiating, or needle-like crystal aggregates. It is primarily found in highly alkaline pegmatites, often appearing as delicate, fibrous sprays associated with other rare earth minerals.
Is this ashcroftine-(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 ashcroftine-(y) with a known reference. Ashcroftine-(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. Ashcroftine-(Y) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ashcroftine-(Y) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: pink, rose-red, colorless.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: acicular or radiating aggregates, fibrous sprays.
Often confused with
Ashcroftine-(Y) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Scolecite is the harder of the two (Mohs 5-5.5 vs. 3.5).
How to tell apart: Mesolite is the harder of the two (Mohs 5 vs. 3.5).
How to tell apart: Thomsonite is the harder of the two (Mohs 5-5.5 vs. 3.5).
Often found alongside ashcroftine-(y)
Minerals reported to co-occur with ashcroftine-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₅Na₂₁Ca(Y,Dy)₂(CO₃)₄Si₂₈O₇₀(OH)₂·nH₂O
- Mohs hardness
- 3.5
- Density
- 2.61 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Tetragonal
- Crystal habit
- Acicular or Radiating Aggregates, Fibrous Sprays
- Cleavage
- Good
- Fluorescence
- Bright White/pale Yellow Under LW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Pegmatites
- Typical price
- $50-500 depending on specimen size and quality
Where rockhounds find ashcroftine-(y)
Classic worldwide localities
- Narssarssuk, Greenland
- Khibiny Massif, Russia
- Lovozero Massif, Russia
Field-hunting tip
Look in alkaline pegmatites country — that is the host setting where ashcroftine-(y) typically forms. If you start seeing microcline, aegirine, analcime in float, you are in the right ground. Field specimens usually show a acicular or radiating aggregates, fibrous sprays habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ashcroftine-(y) on the map
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