Simmonsite is an extremely rare fluoride mineral typically found as small, colorless to pale yellow granular masses within alkaline pegmatite environments. It is chemically distinct for its sodium-lithium-aluminum composition and is primarily prized by advanced mineral collectors for its scarcity and unique locality origins.
Is this simmonsite?
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 simmonsite with a known reference. Simmonsite sits at Mohs 2.5-3, 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: greasy.
- 4Match the color rangeCompare against the expected color range: pale buff cream.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: inclusions, microscopic crystals.
Often confused with
Simmonsite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside simmonsite
Minerals reported to co-occur with simmonsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂LiAlF₆
- Mohs hardness
- 2.5-3
- Density
- 3.05 g/cm³
- Colors
- Pale buff cream
- Streak
- White
- Luster
- Greasy
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Inclusions, microscopic crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage hydrothermal mineral in a breccia pipe that cuts an amazonite-topaz-zinnwaldite pegmatite
Where rockhounds find simmonsite
Classic worldwide localities
- Zapot amazonite-topaz-zinnwaldite pegmatite, Gillis Range, Mineral Co., Nevada (type locality), USA
- Katugin massif, Transbaikalia, Russia
Field-hunting tip
Where it forms: A late-stage hydrothermal mineral in a breccia pipe that cuts an amazonite-topaz-zinnwaldite pegmatite. If you start seeing cryolite, cryolithionite, elpasolite in float, you are in the right ground. Typical habit: inclusions, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify simmonsite?+
Where is simmonsite found?+
What rocks look like simmonsite?+
What minerals are found with simmonsite?+
What kind of rock does simmonsite form in?+
What is simmonsite used for?+
Find simmonsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
