A fascinating natural Moroccan pseudo-stromatolite sand concretion, weighing approximately 316g.
Often known and sold within the mineral trade as a “sand stromatolite” or “desert onion”, these unusual formations are more accurately classified as natural sand concretions rather than true fossil stromatolites.
This substantial specimen has a wonderfully sculptural form, with several joined rounded formations displaying striking concentric ring and onion-like patterns across the main face. Smaller circular structures appear between the larger formations, making this an especially interesting multi-node example.
The warm reddish-orange and sandy brown colouring comes from the mineral-rich sediment, while the naturally rough, granular surface gives the piece plenty of geological character.
These unusual Moroccan concretions are thought to have formed through mineral precipitation within sediment, with barite-rich material cementing sand grains together. Subsequent natural weathering accentuated the distinctive layered and concentric structures visible today.
Details:
- Moroccan pseudo-stromatolite / sand concretion
- Also commonly known as a Sand Stromatolite or Desert Onion
- Barite-cemented sandstone formation
- Natural, unpolished specimen
- Multiple concentric ring formations
- Reddish-orange / sandy brown colouring
- Weight: approximately 316g
- Origin: Morocco
- Individual natural collector's specimen
Please note that this is a completely natural formation, so surface texture, irregularities, small fissures and areas of natural weathering form part of the specimen rather than being manufacturing damage.
The photographs show the exact specimen you will receive.
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