Identification guide · Silicate Minerals
How to Identify Schorl
Schorl is usually black, bluish black, and brownish black with a vitreous luster and is opaque. It has a Mohs hardness of 7. It scratches glass and a steel knife and cannot be scratched by a steel file. Its streak is white to grayish. It is most often confused with Quartz, Tourmaline, and Elbaite; the tests below separate them.
Schorl identification checklist
| Color | Black, Bluish black, Brownish black | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous | 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 | 7 | It scratches glass and a steel knife and cannot be scratched by a steel file. |
| Streak | White to grayish | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Conchoidal to uneven | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 3.1 | Heavier than it looks (specific gravity about 3.1). |
| Crystal system | Trigonal |
Extra tests for Schorl
Glass check. Schorl shares a glassy luster and conchoidal fracture with man-made glass. Glass sits near Mohs 5.5 and often contains round gas bubbles, so a hardness test and a hand lens separate them.
Schorl look-alikes and how to tell them apart
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Schorl vs Quartz →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Schorl vs Tourmaline →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Schorl vs Elbaite →
Both sit near Mohs 7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
Field tips
- Look for black prismatic crystals with strong lengthwise striations and a rounded triangular cross-section.
- Schorl has no cleavage and a hardness of about seven, helping separate it from softer black minerals.
- Crystals may show a domed or wedge-shaped termination typical of tourmaline.
Schorl identification FAQ
How can you tell if a rock is Schorl?
Check the color (black, bluish black, and brownish black), the vitreous luster, a Mohs hardness of 7 and a white to grayish streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Schorl?
Schorl has a Mohs hardness of 7. It scratches glass and a steel knife and cannot be scratched by a steel file.
What is the difference between Schorl and Quartz?
Schorl (Mohs 7, vitreous luster) and Quartz (Mohs 7, vitreous, greasy on fracture surfaces luster) look alike, but hardness, streak and heft usually separate them. See the full Schorl vs Quartz comparison for a side-by-side table.
Is Schorl worth anything?
Entry-level Schorl specimens sell for around $5, typical collector pieces about $50, and premium examples $400 or more depending on size, quality and locality.
What color is Schorl?
Schorl is most often black, bluish black, and brownish black. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
