Rastellum Fossil Value Guide

The Rastellum fossil is a remarkable bivalve mollusk from the Middle Jurassic to Late Cretaceous, prized for its unique 'zipper' appearance. These extinct oysters are highly collectible due to their distinct zigzag shell margins, which evolved to optimize filter feeding in turbulent prehistoric waters.

What affects the value of Rastellum Fossil?

• The clarity and sharpness of the zigzag 'teeth' along the shell margin significantly impact market price.
• Specimens that are fully extracted from the matrix and show both valves intact are more desirable.
• The overall size and preservation of the calcite surface, ranging from $10 to $15 for standard examples.
• The presence of natural coloration or unique mineral crystallization within the sedimentary layers.

How to Identify Rastellum Fossil?

• Look for the signature sharp, zigzag-shaped shell margins that give the specimen its 'zipper' nickname.
• Verify the origin as Madagascar or Europe, where these bivalves are most commonly preserved in sedimentary rock.
• Examine the shell for a heavy calcite composition, which is characteristic of these fossilized mollusks.
• Check for the distinct curved, elongated shape typical of the Rastellum genus compared to standard flat oysters.

History of Rastellum Fossil

Rastellum was a genus of bivalve mollusk that lived from the Middle Jurassic to the Late Cretaceous period. These creatures were characterized by their distinct zigzag-shaped shell margins, which likely helped the oyster filter food more efficiently in turbulent waters. They are frequently found in the fossil beds of Madagascar and parts of Europe.