Mckelveyite-(Y) is a rare carbonate mineral typically found as small, hexagonal platy crystals. It is most famous for its occurrences within the Green River Formation's oil shales and rare alkaline intrusive complexes like Mont Saint-Hilaire. Collectors prize it for its association with exotic rare-earth assemblages and its distinct fluorescence under ultraviolet light.
Is this mckelveyite-(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 mckelveyite-(y) with a known reference. Mckelveyite-(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. Mckelveyite-(Y) leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Mckelveyite-(Y) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-brown, greenish-yellow.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy or tabular crystals, often in hexagonal-shaped clusters.
Often confused with
Mckelveyite-(Y) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside mckelveyite-(y)
Minerals reported to co-occur with mckelveyite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCaBa₃Y(CO₃)₆·3H₂O
- Mohs hardness
- 3.5
- Density
- 3.54 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy or Tabular Crystals, Often in Hexagonal-shaped Clusters
- Cleavage
- Perfect On {0001}
- Fluorescence
- Yellow Under SW UV
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks and Oil Shale Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find mckelveyite-(y)
Classic worldwide localities
- Green River Formation, Wyoming, USA
- Mont Saint-Hilaire, Quebec, Canada
- Lovozero Massif, Kola Peninsula, Russia
Field-hunting tip
Look in alkaline igneous rocks and oil shale deposits country — that is the host setting where mckelveyite-(y) typically forms. If you start seeing searlesite, nahcolite, quartz in float, you are in the right ground. Field specimens usually show a platy or tabular crystals, often in hexagonal-shaped clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mckelveyite-(y)?+
Where is mckelveyite-(y) found?+
How much is mckelveyite-(y) worth?+
Is mckelveyite-(y) safe to handle?+
What rocks look like mckelveyite-(y)?+
What minerals are found with mckelveyite-(y)?+
What kind of rock does mckelveyite-(y) form in?+
What is mckelveyite-(y) used for?+
Find mckelveyite-(y) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
