Schorl is the most abundant species of the tourmaline group, easily recognized by its deep black color and striated, prismatic crystals. It is frequently found in granitic pegmatites and is a staple specimen for almost every mineral collection due to its durability and distinct habit.
Is this schorl?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch schorl with a known reference. Schorl sits at Mohs 7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous.
- 4Match the color rangeCompare against the expected color range: black, brownish black, greenish black, bluish black.
- 5Look at form & habitCrystal system: trigonal. Typical habit: acicular, prismatic, striated.
Often confused with
Schorl vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Schorl is noticeably harder (Mohs 7 vs. 5-6); streak differs, so Schorl leaves white, Arfvedsonite leaves deep bluish gray, gray-green.
How to tell apart: Schorl is noticeably harder (Mohs 7 vs. 5-6); streak differs, so Schorl leaves white, Hornblende leaves grayish-white.
How to tell apart: Schorl is noticeably harder (Mohs 7 vs. 5.5-6); streak differs, so Schorl leaves white, Augite leaves gray-green.
Often found alongside schorl
Minerals reported to co-occur with schorl. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaFe₃Al₆(Si₆O₁₈)(BO₃)₃(OH)₃OH
- Mohs hardness
- 7
- Density
- 3.18-3.22 g/cm³
- Streak
- White
- Luster
- Vitreous to resinous
- Transparency
- Transparent to nearly opaque
- Crystal system
- Trigonal
- Crystal habit
- Acicular, prismatic, striated
- Cleavage
- {1120}, {1011}, very poor
- Rarity
- Common
- Uses
- Collector, Lapidary, Decorative
- Host rock
- In granites and granite pegmatites, high-temperature hydrothermal veins, and some metamorphic rocks; also detrital
Where rockhounds find schorl
13 mapped spotsClassic worldwide localities
- Haddam, Middlesex Co., Connecticut, USA
- Pierrepont, in St. Lawrence Co., New York, USA
- Stony Point, Alexander Co., and near Statesville, Iredell Co., North Carolina, USA
- Little Three mine, Ramona, San Diego Co., California, USA
- Sonnenberg, near St. Andreasberg, Harz Mountains, Germany
- Bovey Tracey, Devon, England
Field-hunting tip
Where it forms: In granites and granite pegmatites, high-temperature hydrothermal veins, and some metamorphic rocks; also detrital. If you start seeing quartz, albite, microcline in float, you are in the right ground. Typical habit: acicular, prismatic, striated. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Maine, Connecticut, Arizona. Start trip planning there.
More schorl photos
Common questions
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Find schorl on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
