Comparison · Minerals
Eudialyte vs Goethite
Eudialyte and Goethite are easy to confuse because both are minerals. Both sit near Mohs 5–5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Eudialyte and Goethite
- Both sit near Mohs 5–5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Eudialyte leaves a white streak on unglazed porcelain, Goethite leaves yellowish brown.
- Goethite feels noticeably heavier for its size (specific gravity 3.3–4.3 versus 2.74–3.1 for Eudialyte).
- Hold a thin edge to the light: Eudialyte is Transparent to translucent, Goethite is Opaque, translucent in thin splinters.
- They overlap in red, brown, and yellow, but Eudialyte also comes in pink and Goethite also comes in black.
- Well-formed crystals give it away: Eudialyte is Trigonal, Goethite is Orthorhombic.
Eudialyte vs Goethite properties
| Property | Eudialyte | Goethite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 5–5.5 | 5–5.5 |
| Luster | Vitreous to greasy | Adamantine to dull/earthy, silky |
| Streak | White | Yellowish brown |
| Transparency | Transparent to translucent | Opaque, translucent in thin splinters |
| Specific gravity | 2.74–3.1 | 3.3–4.3 |
| Crystal system | Trigonal | Orthorhombic |
| Common colors | Red, Pink, Brownish-red, Yellow, Brown | Brown, Yellowish brown, Reddish brown, Black |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Eudialyte and Goethite trade in a similar range, around $20.
About 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.
About Goethite
Goethite is an iron oxide-hydroxide, FeO(OH), and one of the most common iron-bearing minerals, formed by the weathering of other iron minerals such as pyrite, magnetite, and siderite. It crystallizes in the orthorhombic system but rarely shows well-formed crystals, instead forming botryoidal, stalactitic, or earthy masses. Named for the German writer and naturalist Johann Wolfgang von Goethe, it is a major constituent of the mineral mixture commonly called limonite.
Eudialyte vs Goethite FAQ
Is Eudialyte the same as Goethite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 5–5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Eudialyte from Goethite?
Both sit near Mohs 5–5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Eudialyte leaves a white streak on unglazed porcelain, Goethite leaves yellowish brown. Goethite feels noticeably heavier for its size (specific gravity 3.3–4.3 versus 2.74–3.1 for Eudialyte).
Which is harder, Eudialyte or Goethite?
They are about equally hard, both near Mohs 5–5.5.
Which is more valuable, Eudialyte or Goethite?
Typical specimens of Eudialyte and Goethite trade in a similar range, around $20.
