A silicified mastodon tusk is ancient organic material replaced atom by atom by chalcedony over geological time. Look for the ivory-like internal growth rings or cross-hatched Schreger lines that confirm its biological origin. It is prized both for its paleontological significance and for taking a high polish when cut.
Is this silicified mastodon tusk?
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 silicified mastodon tusk with a known reference. Silicified Mastodon Tusk sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Silicified Mastodon Tusk leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Silicified Mastodon Tusk typically shows a waxy to vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, cream, tan, brown, gray.
- 5Look at form & habitTypical habit: massive pseudomorph.
Often confused with
Silicified Mastodon Tusk vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside silicified mastodon tusk
Minerals reported to co-occur with silicified mastodon tusk. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- SiO₂
- Mohs hardness
- 6.5-7
- Density
- 2.6-2.7 g/cm³
- Streak
- White
- Luster
- Waxy to Vitreous
- Transparency
- Opaque
- Crystal habit
- Massive Pseudomorph
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Lapidary
- Host rock
- River Gravels, Pleistocene Alluvial Deposits
Where rockhounds find silicified mastodon tusk
1 mapped spotsClassic worldwide localities
- Florida
- South Carolina
- Alaska
- Siberia
Field-hunting tip
Look in river gravels, pleistocene alluvial deposits country, the host setting where silicified mastodon tusk typically forms. If you start seeing quartz, chalcedony, goethite in float, you are in the right ground. Field specimens usually show a massive pseudomorph habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nebraska. Start trip planning there.
Common questions
How do you identify silicified mastodon tusk?+
Where is silicified mastodon tusk found?+
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Find silicified mastodon tusk on the map
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