Comparison · Metamorphic Rocks
Metaconglomerate vs Skarn
Metaconglomerate and Skarn are easy to confuse because both are metamorphic rocks. Metaconglomerate is harder (Mohs 6.5) than Skarn (Mohs 5.5), so Metaconglomerate will scratch Skarn and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Metaconglomerate and Skarn
- Metaconglomerate is harder (Mohs 6.5) than Skarn (Mohs 5.5), so Metaconglomerate will scratch Skarn and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
- Streak color differs: Metaconglomerate leaves a variable by pebbles and matrix streak on unglazed porcelain, Skarn leaves variable by mineral content.
- They overlap in gray, white, brown, red, and black, but Skarn also comes in green.
Metaconglomerate vs Skarn properties
| Property | Metaconglomerate | Skarn |
|---|---|---|
| Type | Metamorphic Rocks | Metamorphic Rocks |
| Mohs hardness | 6.5 | 5.5 |
| Luster | dull | dull |
| Streak | Variable by pebbles and matrix | Variable by mineral content |
| Transparency | opaque | opaque |
| Specific gravity | 2.65 | 3.1 |
| Crystal system | varies | varies |
| Common colors | Gray, White, Tan, Red, Brown, Black | Green, Brown, White, Gray, Red, Black |
| Rarity | uncommon | uncommon |
| Typical specimen value | $1–$75+ | $2–$150+ |
Which is more valuable?
Skarn is usually the more valuable of the two: a typical collector specimen runs about $20 against $10 for Metaconglomerate, and premium Skarn can reach $150 or more.
About Metaconglomerate
Metaconglomerate is a metamorphosed conglomerate with rounded pebbles or cobbles in a recrystallized matrix. Pebbles may appear stretched, flattened, or locked into a hard metamorphic rock.
About Skarn
Skarn is a calc-silicate metamorphic rock formed where hot intrusive fluids alter carbonate rocks. It can be green, brown, white, red, or mixed and may contain garnet, pyroxene, epidote, or ore minerals.
Metaconglomerate vs Skarn FAQ
Is Metaconglomerate the same as Skarn?
No. Both are metamorphic rocks, but they are distinct rock types with different hardness, streak or luster. Metaconglomerate is harder (Mohs 6.5) than Skarn (Mohs 5.5), so Metaconglomerate will scratch Skarn and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
How can you tell Metaconglomerate from Skarn?
Metaconglomerate is harder (Mohs 6.5) than Skarn (Mohs 5.5), so Metaconglomerate will scratch Skarn and not the other way round. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. Streak color differs: Metaconglomerate leaves a variable by pebbles and matrix streak on unglazed porcelain, Skarn leaves variable by mineral content. They overlap in gray, white, brown, red, and black, but Skarn also comes in green.
Which is harder, Metaconglomerate or Skarn?
Metaconglomerate is harder: Mohs 6.5 against Mohs 5.5 for Skarn.
Which is more valuable, Metaconglomerate or Skarn?
Skarn is usually the more valuable of the two: a typical collector specimen runs about $20 against $10 for Metaconglomerate, and premium Skarn can reach $150 or more.
