Eudialyte is a complex cyclosilicate known for its striking red or pink coloration and its association with rare alkaline rocks. Collectors prize it for its well-formed rhombohedral crystals, though it is frequently found in massive, granular, or anhedral forms within igneous complexes.
Is this eudialyte?
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 eudialyte with a known reference. Eudialyte 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. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to dull.
- 4Match the color rangeCompare against the expected color range: red, pink, brown, yellow, colorless, pinkish red, yellowish brown, violet.
- 5Look at form & habitCrystal system: trigonal. Typical habit: massive, tabular.
Often confused with
Eudialyte vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside eudialyte
Minerals reported to co-occur with eudialyte. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₅Ca₆Fe₃Zr₃Si(Si₂₅O₇₃)(O,OH,H₂O)₃(Cl,OH)₂
- Mohs hardness
- 5-6
- Density
- 2.74-3.10 g/cm³
- Streak
- White
- Luster
- Vitreous to dull
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Massive, tabular
- Cleavage
- Perfect to indistinct on {0001}, imperfect on {1120}
- Rarity
- Uncommon
- Uses
- Collector, Lapidary
- Host rock
- In nepheline syenites, alkalic granites, and associated pegmatites; may be a major constituent, of both magmatic and late-stage pneumatolytic origin
Where rockhounds find eudialyte
1 mapped spotsClassic worldwide localities
- Magnet Cove, Hot Spring Co., Arkansas, USA
- Point of Rocks, Colfax Co., and in a Pajarito Mountain, Otero Co., New Mexico, USA
- Langesundsfjord, Norway
- Lovozero and Khibiny massifs, Kola Peninsula, Russia
- Barynga Ridge, Taimyr, Russia
- Burpala massif, about 120 km north of Lake Baikal, eastern Siberia, Russia
Field-hunting tip
Where it forms: In nepheline syenites, alkalic granites, and associated pegmatites; may be a major constituent, of both magmatic and late-stage pneumatolytic origin. If you start seeing microcline, nepheline, aegirine in float, you are in the right ground. Typical habit: massive, tabular. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Arkansas. Start trip planning there.
Common questions
How do you identify eudialyte?+
Where is eudialyte found?+
Can I find eudialyte in the United States?+
Is eudialyte safe to handle?+
What rocks look like eudialyte?+
What minerals are found with eudialyte?+
What kind of rock does eudialyte form in?+
What is eudialyte used for?+
Find eudialyte on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
