Agatized Cycad Wood is a fossilized remain of ancient cycads where organic material has been replaced by microcrystalline silica.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.
More agatized cycad wood photos
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?+
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Find agatized cycad wood on the map
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