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Septarian nodules are concretions containing angular cavities or cracks called septaria. They are thought to form within layers of sedimentary strata before the rest of the sediment is hardened into rock. The concretionary cement often makes the concretion harder and more resistant to weathering processes than the surrounding strata. The septaria sometimes contain crystals precipitated from circulating groundwater solutions, most commonly of calcite.

The processes responsible for creating the septaria are not well understood. Proposed mechanisms include the shrinkage of the concretions' clay or organic rich cores due to dehydration, the expansion of gases produced by the decay of organic matter, and brittle fracturing of the concretion by earthquakes or compression.

Septarian nodules are sought after by rockhounds as collectable geological curiosities and as well as lapidary rough. When septarian nodules are sectioned, their exposed interiors sometimes reveal striking and aesthetic patterns.

It was while polishing a cabochon we cut from one of these Oujda, Morocco septarian nodules and that we really began noticing the small pyrite crystals included in some of them. Very cool!

SeptarianPair2 - Polished Septarian Pair - $24.95

Locality: Oujda, Morocco Approximate Size: 65mm long x 42mm wide x 26mm thick. Please note the image above may be larger than life to help show the fine details. Approximate Pair Weight: 94.3 grams

SeptarianPair9 - Polished Septarian Pair - $29.95

Locality: Oujda, Morocco Approximate Size: 35.5mm long x 34.5mm wide x 22.1mm thick. Please note the image above may be larger than life to help show the fine details. Approximate Pair Weight: 34.3 grams

SeptarianPair11 - Polished Septarian Pair - $34.95

Locality: Oujda, Morocco Approximate Size: 75.8mm long x 58.2mm wide x 31.0mm thick. Please note the image above may be larger than life to help show the fine details. Approximate Pair Weight: 172.5 grams

SeptarianPair12 - Polished Septarian Pair - $24.95

Locality: Oujda, Morocco Approximate Size: 60.1mm long x 51.7mm wide x 33.2mm thick. Please note the image above may be larger than life to help show the fine details. Approximate Pair Weight: 149.9 grams

SeptarianPair15 - Polished Septarian Pair - $39.95

Locality: Oujda, Morocco Approximate Size: 69.1mm long x 55.0mm wide x 24.5mm thick. Please note the image above may be larger than life to help show the fine details. Approximate Pair Weight: 128.0 grams

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