Syenite is a coarse-grained plutonic igneous rock similar to granite but characterized by a lack of or very low quartz content. It is primarily composed of alkali feldspar with subordinate mafic minerals like hornblende or biotite. Collectors should look for its distinctive speckled appearance and interlocking crystalline texture, commonly found in deep-seated intrusive bodies.
Is this 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 syenite with a known reference. Syenite sits at Mohs 6, softer than the next harder reference, harder than the previous one.
- 2Read the textureLook at a fresh break with a hand lens. Grain size: Coarse-grained.
- 3Pick out the mineralsComposition: Predominantly alkali feldspar (usually orthoclase), with hornblende and clinopyroxene; quartz under 5 percent if present. 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, pink, white, speckled.
Often confused with
Syenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside syenite
Minerals reported to co-occur with syenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 6
- Density
- 2.7-2.9 g/cm³
- Luster
- Vitreous
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Building stone, Decorative, Ornamental
- Host rock
- plutonic igneous
- Grain size
- Coarse-grained
- Composition
- Predominantly alkali feldspar (usually orthoclase), with hornblende and clinopyroxene; quartz under 5 percent if present
Where rockhounds find syenite
1 mapped spotsClassic worldwide localities
- Norway
- Canada
- Germany
- United States
- Egypt
Field-hunting tip
Where it forms: plutonic igneous. If you start seeing feldspar, biotite, hornblende 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 syenite?+
Where is syenite found?+
Can I find syenite in the United States?+
What rocks look like syenite?+
What minerals are found with syenite?+
What kind of rock does syenite form in?+
What is syenite used for?+
Find syenite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
