Agatized Cycad Wood is a fossilized remain of ancient cycads where organic material has been replaced by microcrystalline silica. Collectors look for well-defined internal structure, such as the characteristic pith, cortex, and vascular bundles visible in polished cross-sections.
Is this agatized cycad wood?
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 agatized cycad wood with a known reference. Agatized Cycad Wood sits at Mohs 6.5-7, softer than the next harder reference, harder than the previous one.
- 2Name the organismDecide what left the fossil before worrying about the rock. Organism: Cycad-like bennettitalean plant (genus Cycadeoidea). Age: Cretaceous, possibly Jurassic.
- 3Check the preservationPreservation: Petrified by permineralization and replacement; agatized. That controls the weight, the hardness and how the piece takes a polish.
- 4Read the lusterHold the specimen under a strong light. Luster: waxy.
- 5Match the color rangeCompare against the expected color range: brown, tan, gray, white, black, red.
Often confused with
Agatized Cycad Wood vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside agatized cycad wood
Minerals reported to co-occur with agatized cycad wood. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 6.5-7
- Density
- 2.6-2.7 g/cm³
- Luster
- Waxy
- Transparency
- Translucent
- Rarity
- Uncommon
- Uses
- Lapidary, Collector, Decorative
- Host rock
- sedimentary strata
- Organism
- Cycad-like bennettitalean plant (genus Cycadeoidea)
- Age
- Cretaceous, possibly Jurassic
- Preservation
- Petrified by permineralization and replacement; agatized
Where rockhounds find agatized cycad wood
Classic worldwide localities
- Black Hills, South Dakota USA
- Utah, USA
- Wyoming, USA
- Madagascar
Field-hunting tip
Where it forms: sedimentary strata. If you start seeing quartz, chalcedony, jasper in float, you are in the right ground.
Common questions
How do you identify agatized cycad wood?+
Where is agatized cycad wood found?+
What rocks look like agatized cycad wood?+
What minerals are found with agatized cycad wood?+
What kind of rock does agatized cycad wood form in?+
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Find agatized cycad wood on the map
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