The official GemStone IV encyclopedia.
Sard is a red or brown variant of chalcedony. It is often found with onyx.
List of Sards
an umber sard
|Description: The rough edges of this stone attest to past fractures. The hue varies from place to place on the surface, running the gamut between dark yellow and a brown so deep that it is almost black, but a faint translucency pervades it in all places.|