Groatite is a rare phosphate mineral typically found as small, yellowish-green grains within phosphate-rich concretions in the Yukon Territory. It is highly sought after by collectors of rare phosphate minerals due to its scarcity and distinct paragenesis in low-temperature sedimentary environments.
Is this groatite?
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 groatite with a known reference. Groatite sits at Mohs 3, 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: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, pale yellow, pale orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains and small aggregates.
Often confused with
Groatite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside groatite
Minerals reported to co-occur with groatite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- □NaCaMn₂(PO₄)(HPO₄)₂
- Mohs hardness
- 3
- Density
- 3.213 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to subhedral grains and small aggregates
- Cleavage
- None observed
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage mineral, most likely derived from the dissolution of lithiophosphate and lithiophilite, in a spodumene-rich portion of a zoned petalite-subgroup pegmatite
Where rockhounds find groatite
Classic worldwide localities
- Tanco Mine, Lake Bernic, Manitoba, Canada
Field-hunting tip
Where it forms: A late-stage mineral, most likely derived from the dissolution of lithiophosphate and lithiophilite, in a spodumene-rich portion of a zoned petalite-subgroup pegmatite. If you start seeing whitlockite, crandallite, quartz in float, you are in the right ground. Typical habit: anhedral to subhedral grains and small aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify groatite?+
Where is groatite found?+
What rocks look like groatite?+
What minerals are found with groatite?+
What kind of rock does groatite form in?+
What is groatite used for?+
Find groatite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
