Nepheline syenite is a silica-deficient, phaneritic plutonic rock composed primarily of alkali feldspar and nepheline. It often appears similar to granite but lacks quartz, making it a key indicator of alkaline magmatic environments. Collectors look for its characteristic speckled appearance and association with rare alkali-rich mineral assemblages.
Is this nepheline syenite?
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 nepheline syenite with a known reference. Nepheline Syenite sits at Mohs 5.5-6, softer than the next harder reference, harder than the previous one.
- 2Read the textureLook at a fresh break with a hand lens. Texture: Plutonic. Grain size: Coarse-grained.
- 3Pick out the mineralsComposition: Mainly alkali feldspar (often perthite) and nepheline, with no primary quartz; minor sodalite, sodium-rich pyroxene, biotite, titanite and zircon. Identify the two or three most abundant grains.
- 4Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 5Match the color rangeCompare against the expected color range: gray, white, pink, greenish-gray.
Often confused with
Nepheline Syenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside nepheline syenite
Minerals reported to co-occur with nepheline syenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 5.5-6
- Density
- 2.55-2.65 g/cm³
- Luster
- Vitreous
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Industrial, Architectural, Collector
- Host rock
- plutonic igneous complex
- Texture
- Plutonic
- Grain size
- Coarse-grained
- Composition
- Mainly alkali feldspar (often perthite) and nepheline, with no primary quartz; minor sodalite, sodium-rich pyroxene, biotite, titanite and zircon
Where rockhounds find nepheline syenite
1 mapped spotsClassic worldwide localities
- Ontario, Canada
- Kola Peninsula, Russia
- Norway
- Arkansas, USA
- Greenland
Field-hunting tip
Where it forms: plutonic igneous complex. If you start seeing nepheline, orthoclase, albite in float, you are in the right ground. In the U.S., the densest reported localities are in Arkansas. Start trip planning there.
Common questions
How do you identify nepheline syenite?+
Where is nepheline syenite found?+
Can I find nepheline syenite in the United States?+
What rocks look like nepheline syenite?+
What minerals are found with nepheline syenite?+
What kind of rock does nepheline syenite form in?+
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Find nepheline syenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
