Neighborite is a rare sodium magnesium fluoride mineral typically found in evaporite deposits associated with alkaline rocks. It most commonly occurs as small, colorless to brownish pseudocubic crystals embedded within oil shale formations.
Is this neighborite?
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 neighborite with a known reference. Neighborite sits at Mohs 4.5, 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 to dull, greasy.
- 4Match the color rangeCompare against the expected color range: colorless, pink, reddish brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: octahedral crystals.
Often confused with
Neighborite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside neighborite
Minerals reported to co-occur with neighborite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaMgF₃
- Mohs hardness
- 4.5
- Density
- 3.03 g/cm³
- Streak
- White
- Luster
- Vitreous to dull, greasy
- Transparency
- Transparent to opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Octahedral crystals
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- An authigenic mineral, formed under aluminum-deficient conditions in dolomitic oil shale (South Ouray, Utah, USA); in metamorphosed tuff and clayey carbonate sediments (Ural Mountains, Russia)
Where rockhounds find neighborite
Classic worldwide localities
- South Ouray and Sun Havenstrite wells, about 8 km south-southeast of South Ouray, Uintah Co., Utah, USA
- Mont Saint-Hilaire, Quebec, Canada
- Lake Gjerdingen, Nordmarka, Norway
- Lovozero, Khibiny, and Kovdor massifs, Kola Peninsula, the Ural Mountains, Russia
Field-hunting tip
Where it forms: An authigenic mineral, formed under aluminum-deficient conditions in dolomitic oil shale (South Ouray, Utah, USA); in metamorphosed tuff and clayey carbonate sediments (Ural Mountains, Russia). If you start seeing burbankite, nahcolite, wurtzite in float, you are in the right ground. Typical habit: octahedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify neighborite?+
Where is neighborite found?+
What rocks look like neighborite?+
What minerals are found with neighborite?+
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Find neighborite on the map
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