Comparison · Silicate Minerals
Natrolite vs Stilbite
Natrolite and Stilbite are easy to confuse because both are silicate minerals. Natrolite is harder (Mohs 5.5) than Stilbite (Mohs 3.75), so Natrolite will scratch Stilbite and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Natrolite and Stilbite
- Natrolite is harder (Mohs 5.5) than Stilbite (Mohs 3.75), so Natrolite will scratch Stilbite and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
- They overlap in pink and yellow, but Natrolite also comes in clear and gray and Stilbite also comes in white and brown.
- Well-formed crystals give it away: Natrolite is orthorhombic, Stilbite is monoclinic.
Natrolite vs Stilbite properties
| Property | Natrolite | Stilbite |
|---|---|---|
| Type | Silicate Minerals | Silicate Minerals |
| Mohs hardness | 5.5 | 3.75 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | transparent |
| Specific gravity | 2.25 | 2.2 |
| Crystal system | orthorhombic | monoclinic |
| Common colors | Colorless, White, Pink, Yellow, Gray | White, Pink, Salmon, Yellow, Brown |
| Rarity | uncommon | common |
| Typical specimen value | $8–$250+ | $5–$250+ |
Which is more valuable?
Natrolite is usually the more valuable of the two: a typical collector specimen runs about $45 against $40 for Stilbite, and premium Natrolite can reach $250 or more.
About Natrolite
Natrolite is a sodium-rich zeolite mineral that forms delicate, slender prismatic crystals, often gathered into radiating sprays. It typically occurs in cavities of basalt and is valued by collectors for its needle-like sprays.
About Stilbite
Stilbite is a calcium-rich zeolite mineral known for its distinctive sheaf-like or bowtie-shaped crystal aggregates. It commonly occurs as white to salmon-pink crystals lining cavities in basalt, often with other zeolites.
Natrolite vs Stilbite FAQ
Is Natrolite the same as Stilbite?
No. Both are silicate minerals, but they are distinct species with different hardness, streak or luster. Natrolite is harder (Mohs 5.5) than Stilbite (Mohs 3.75), so Natrolite will scratch Stilbite and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
How can you tell Natrolite from Stilbite?
Natrolite is harder (Mohs 5.5) than Stilbite (Mohs 3.75), so Natrolite will scratch Stilbite and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. They overlap in pink and yellow, but Natrolite also comes in clear and gray and Stilbite also comes in white and brown. Well-formed crystals give it away: Natrolite is orthorhombic, Stilbite is monoclinic.
Which is harder, Natrolite or Stilbite?
Natrolite is harder: Mohs 5.5 against Mohs 3.75 for Stilbite.
Which is more valuable, Natrolite or Stilbite?
Natrolite is usually the more valuable of the two: a typical collector specimen runs about $45 against $40 for Stilbite, and premium Natrolite can reach $250 or more.
