Identification guide · Metamorphic Rocks
How to Identify Migmatite
Migmatite shows a banded or swirled appearance combining darker, fine-grained metamorphic layers with lighter, coarser, granite-like veins and pods, and luster and streak vary with the specific minerals present in each layer. Hardness generally falls in the range of common silicate rocks, around 5.5 to 6.5, resisting a steel knife. Fracture is uneven, following the complex internal banding rather than any single plane. It is most easily confused with strongly banded gneiss, though migmatite's leucosome veins typically show a more clearly igneous, granite-like texture.
Migmatite identification checklist
| Color | Gray and white banded, Pink and black, Light and dark layered | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous to dull (banded) | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 5–7 | It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will. |
| Fracture | Uneven | |
| Specific gravity | 2.65–2.75 | Ordinary rock-like heft (specific gravity about 2.7), similar to quartz. |
Migmatite look-alikes and how to tell them apart
Both sit near Mohs 5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Migmatite vs Gneiss →
Quartz is harder (Mohs 7) than Migmatite (Mohs 5–7), so Quartz will scratch Migmatite 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. Migmatite vs Quartz →
Quartzite is harder (Mohs 7) than Migmatite (Mohs 5–7), so Quartzite will scratch Migmatite 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. Migmatite vs Quartzite →
Both sit near Mohs 5–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Migmatite identification FAQ
How can you tell if a rock is Migmatite?
Check the color (gray and white banded, pink and black, and light and dark layered), the vitreous to dull (banded) luster, a Mohs hardness of 5–7. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Migmatite?
Migmatite has a Mohs hardness of 5–7. It is about as hard as window glass: a knife barely marks it, while a steel file (Mohs 6.5) will.
What is the difference between Migmatite and Gneiss?
Migmatite (Mohs 5–7, vitreous to dull (banded) luster) and Gneiss (Mohs 6–7, vitreous to glimmering (mica-rich bands) luster) look alike, but hardness, streak and heft usually separate them. See the full Migmatite vs Gneiss comparison for a side-by-side table.
Is Migmatite worth anything?
Entry-level Migmatite specimens sell for around $1, typical collector pieces about $10, and premium examples $75 or more depending on size, quality and locality.
What color is Migmatite?
Migmatite is most often gray and white banded, pink and black, and light and dark layered. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
