Weberite is a rare fluoride mineral discovered in the famous cryolite deposit of Ivigtut, Greenland. It typically occurs as massive, granular white or brownish masses and is highly prized by mineral collectors specializing in rare halides or pegmatite suites.
Is this weberite?
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 weberite with a known reference. Weberite 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: greenish, gray, grayish white, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: anhedral grains, massive.
Often confused with
Weberite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Weberite is noticeably harder (Mohs 3.5 vs. 2.5).
How to tell apart: Prosopite is the harder of the two (Mohs 4.5 vs. 3.5).
How to tell apart: Weberite is noticeably harder (Mohs 3.5 vs. 2); luster reads vitreous on Weberite and dull on Gearksutite.
Often found alongside weberite
Minerals reported to co-occur with weberite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂MgAlF₇
- Mohs hardness
- 3.5
- Density
- 2.96 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Anhedral grains, massive
- Cleavage
- {011}, poor; {010}, indistinct
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In the cryolite deposit and overlying pegmatite (Ivigtut, Greenland)
Where rockhounds find weberite
Classic worldwide localities
- St. Peters Dome, near Pikes Peak, El Paso Co., and in the Goldie carbonatite, McClure Mountain-Iron Mountain, Fremont Co., Colorado, USA
- Zapot pegmatite, 25 km northeast of Hawthorne, Fitting district, Mineral Co., Nevada, USA
- Ivigtut cryolite deposit, southwestern Greenland
- Mt. Cleveland tin mine, western Tasmania, Australia
- Perga, Volyn, Ukraine
Field-hunting tip
Where it forms: In the cryolite deposit and overlying pegmatite (Ivigtut, Greenland). If you start seeing cryolite, chiolite, jarlite in float, you are in the right ground. Typical habit: anhedral grains, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify weberite?+
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What rocks look like weberite?+
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Find weberite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
