Comparison · Silicate Minerals
Nepheline vs Orthoclase
Nepheline and Orthoclase are easy to confuse because both are silicate minerals. Both sit near Mohs 6, 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 Nepheline and Orthoclase
- Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- They overlap in clear and yellow, but Nepheline also comes in gray, green, and red and Orthoclase also comes in pink.
- Well-formed crystals give it away: Nepheline is hexagonal, Orthoclase is monoclinic.
Nepheline vs Orthoclase properties
| Property | Nepheline | Orthoclase |
|---|---|---|
| Type | Silicate Minerals | Silicate Minerals |
| Mohs hardness | 6 | 6 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | translucent | translucent |
| Specific gravity | 2.6 | 2.56 |
| Crystal system | hexagonal | monoclinic |
| Common colors | Colorless, White, Gray, Yellowish, Greenish, Reddish | Colorless, White, Cream, Pink, Yellow |
| Rarity | uncommon | common |
| Typical specimen value | $5–$150+ | $5–$250+ |
Which is more valuable?
Orthoclase is usually the more valuable of the two: a typical collector specimen runs about $35 against $30 for Nepheline, and premium Orthoclase can reach $250 or more.
About Nepheline
Nepheline is a sodium and potassium aluminosilicate of the feldspathoid group, found in silica-poor igneous rocks. It usually appears as gray, greasy-looking masses and grains rather than well-formed crystals.
About Orthoclase
Orthoclase is a common potassium feldspar and a major rock-forming mineral in granitic rocks. It defines hardness 6 on the Mohs scale and appears as cream, pink, or colorless crystals and masses.
Nepheline vs Orthoclase FAQ
Is Nepheline the same as Orthoclase?
No. Both are silicate minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Nepheline from Orthoclase?
Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. They overlap in clear and yellow, but Nepheline also comes in gray, green, and red and Orthoclase also comes in pink. Well-formed crystals give it away: Nepheline is hexagonal, Orthoclase is monoclinic.
Which is harder, Nepheline or Orthoclase?
They are about equally hard, both near Mohs 6.
Which is more valuable, Nepheline or Orthoclase?
Orthoclase is usually the more valuable of the two: a typical collector specimen runs about $35 against $30 for Nepheline, and premium Orthoclase can reach $250 or more.
