White Desert Fossil Collection
Hexactinellid Glass Sponge
These remarkable specimens are fossil glass sponges of the class Hexactinellida, preserved within the ancient Tethyan seafloor chalk of the White Desert. The original siliceous sponge skeleton has been replaced by goethite and manganese-oxide minerals, producing a deep blue-black coloration with a subtle metallic luster.
Collector’s Gallery
Select specimens available for acquisition from an established White Desert source. Each piece is unique and offered as-is.
Cabinet-Grade Glass Sponge #S1
Exceptional 3D preservation showing the internal canal structure. Goethite/Manganese-Oxide pseudomorph with indigo luster.
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Hexactinellid Cluster #S2
A complex, multi-layered specimen showing overlapping skeletal lattices. Remarkable mineralization detail.
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Goethite Sponge Fragment #S3
A dense, highly mineralized fragment with deep metallic luster. Ideal for study of the pseudomorphic replacement.
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Articulated Brachiopod #B1
A complete double-valve specimen with sharp radial costae and a distinct hinge line. Fully mineralized goethite replacement.
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Large Lamp Shell #B2 (Selection A)
Robust single-valve specimen showing clear growth lines and significant iron mineralization.
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Lamp Shell Specimen #B3 (Selection B)
Well-preserved rib architecture. This specimen displays a rich, earthy goethite patina.
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Micro-Costate Brachiopod #B4
A smaller, elegant specimen with incredibly fine costae preservation. Exceptionally sharp for its size.
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White Desert Faunal Study Set #SSB1
A curated set containing select examples of both glass sponges and brachiopods representing the full range of White Desert goethite-mineralized marine fauna.
Inquire for PurchaseThe hexactinellid glass sponges and brachiopods described here were recovered from the same ancient White Desert chalk deposits — neighbors on the same Tethyan seafloor over 70 million years ago.