Ammolite Negative Cap Slab - CGSS8

Flat slab of ammolite negative cap, from the Bearpaw Formation of Southern Alberta. Red and pink run through the centre in a fine crackle pattern, with orange, yellow and green around the edge, all on dark natural shale.

What is negative cap? When an ammonite shell split from the rock around it, part of the ammolite layer sometimes stayed stuck to the rock instead of the shell. That piece is called negative cap: genuine ammolite on its natural shale, showing the colour from the inside of the shell.

This slab is one half of a matching pair. Its partner is listed as CGSS7.