Eudialyte
Eudialyte is a complex, often pink to red zirconium silicate mineral crystallizing in the trigonal system, associated almost exclusively with unusual alkaline igneous rocks called nepheline syenites. Its name derives from Greek words meaning well decomposable, a reference to how readily it dissolves in acid compared to most silicate minerals. Nicknamed Saami blood stone in parts of Scandinavia, eudialyte's vivid coloring and rarity make it a favorite among collectors of unusual silicate minerals.
Eudialyte properties at a glance
| Type | Minerals |
|---|---|
| Chemical formula | Na4(Ca,Ce)2(Fe,Mn,Y)ZrSi8O22(OH,Cl)2 |
| Mohs hardness | 5–5.5 |
| Crystal system | Trigonal |
| Luster | Vitreous to greasy |
| Streak | White |
| Cleavage | Indistinct/poor on {0001} and {1010} |
| Fracture | Conchoidal to uneven |
| Specific gravity | 2.74–3.1 |
| Transparency | Transparent to translucent |
| Common colors | Red, Pink, Brownish-red, Yellow, Brown |
| Rarity | common |
Geology & background
Eudialyte crystallizes in rare alkaline igneous complexes formed from magmas unusually enriched in sodium, zirconium, and rare earth elements, conditions found in relatively few places on Earth. The Kola Peninsula of Russia and Ilimaussaq in Greenland host some of the world's most significant eudialyte deposits, both associated with layered nepheline syenite intrusions that also contain other rare minerals unique to alkaline rock suites. Smaller but collectible occurrences appear at Quebec's Mont Saint-Hilaire, a locality famous among mineral collectors for its unusual mineral diversity.
Because eudialyte forms only in these specialized alkaline rocks, most specimens occur embedded within a matrix of feldspar, nepheline, and aegirine rather than as loose crystals, and collectors typically value pieces showing strong color contrast between the red eudialyte and its host rock. Some eudialyte deposits are being explored as potential sources of rare earth elements and zirconium, adding an economic dimension to what has traditionally been a purely aesthetic collector mineral. Fresh, undamaged red color is prized, since weathering can dull the mineral to brown over time.
How to identify Eudialyte
Eudialyte typically appears pink, red, or brownish-red, occasionally yellow or violet, embedded within a coarse-grained igneous matrix, with a vitreous luster on fresh surfaces. Its streak is white, hardness falls between 5 and 6, and it shows poor to indistinct cleavage, breaking with a conchoidal fracture. It is almost always found intergrown with feldspar, nepheline, and dark sodium-rich pyroxene or amphibole rather than as free-standing crystals. Its association with alkaline igneous rock and distinctive red color make it hard to confuse with anything except garnet, which lacks eudialyte's typical host-rock context.
- Compare the specimen's color, luster, crystal habit, grain size, streak, and locality before confirming.
- Use multiple photos when possible, including a fresh surface and a close view of texture.
Where Eudialyte is found
Reported from multiple localities worldwide; verify locality against specimen provenance when available.
How much is Eudialyte worth?
| Entry-level specimen | $2 |
|---|---|
| Typical collector specimen | $20 |
| Premium specimen | $150+ |
Value depends on size, crystal quality, color, locality, rarity, damage, and provenance.
Common uses
- Collector specimens
- Education
- Field identification
- Industrial or lapidary use when suitable
Interesting facts
- Eudialyte's Greek-derived name means well decomposable, chosen because it dissolves in acid far more readily than most silicate minerals.
- Some Scandinavian traditions call eudialyte Saami blood stone after the indigenous Saami people of the region where striking red specimens are found.
- Certain eudialyte deposits are now studied as potential sources of rare earth elements needed for modern electronics and magnets.
Care & safety
Handle as a collector specimen until hardness, cleavage, and fracture are verified.
Avoid inhaling dust. Do not cut, grind, or polish unknown specimens without eye protection and a proper respirator.
.jpg?width=320)
.jpg?width=320)