Grenmarite is a rare member of the wöhlerite group primarily found in alkaline igneous environments. It typically forms yellow-to-brown prismatic crystals that are chemically complex and often indistinguishable from related minerals without analytical testing. Collectors generally source this mineral from the specialized pegmatites of the Langesundsfjord region in Norway.
Is this grenmarite?
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 grenmarite with a known reference. Grenmarite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Grenmarite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Grenmarite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals.
Often confused with
Grenmarite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside grenmarite
Minerals reported to co-occur with grenmarite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaCa₂MnZr(Si₂O₇)OF
- Mohs hardness
- 5-6
- Density
- 3.37 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nepheline Syenite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find grenmarite
Classic worldwide localities
- Langesundsfjord, Norway
Field-hunting tip
Look in nepheline syenite pegmatites country — that is the host setting where grenmarite typically forms. If you start seeing nepheline, aegirine, microcline in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find grenmarite on the map
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