Pentramites echinoderm fossil

Blastoids are extinct stalked sea creatures, related to modern sea urchins, sea stars and sand dollars.  Like most modern echinoderms, they had star-like symmetry, in this case with five points.  This specimen is mounted on a gold coloured base.

1/4 inch (0.6 cm) in diameter and just under 7/16 inch (1.1 cm) tall.