Obsidian nodules, often known as Apache Tears, are naturally rounded, pebble-like masses of volcanic glass. They are typically found embedded within softer perlite matrix and are prized by collectors for their smooth, water-worn appearance and conchoidal fracturing.
Is this obsidian nodules?
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 obsidian nodules with a known reference. Obsidian Nodules sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Obsidian Nodules leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Obsidian Nodules typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: black, brown, gray.
- 5Look at form & habitTypical habit: rounded nodules.
Often confused with
Obsidian Nodules vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside obsidian nodules
Minerals reported to co-occur with obsidian nodules. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 5-5.5
- Density
- 2.4 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal habit
- Rounded Nodules
- Cleavage
- None
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- Rhyolitic Volcanic Ash and Perlite
- Typical price
- $2-20 per nodule
Where rockhounds find obsidian nodules
Classic worldwide localities
- Arizona, USA
- Nevada, USA
- Mexico
- Iceland
Field-hunting tip
Look in rhyolitic volcanic ash and perlite country — that is the host setting where obsidian nodules typically forms. If you start seeing perlite, rhyolite, quartz in float, you are in the right ground. Field specimens usually show a rounded nodules habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find obsidian nodules on the map
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