39mm x 23mm
Brecciated, or "ruin" agates are encountered infrequently in Scotland, as far as I am aware. I have seen an example or two at St Cyrus, but at Usan they occur more frequently, perhaps as a result of damage to agates while still in-situ, by the powerful tides in the area.
This stone clearly began its existence as an orange fortification agate, albeit one showing particularly fine banding. How later, the central core of this piece (where in general fortification banding in finer resulting in a greater density) was dissolved by an intrusion of blue-grey chalcedony, I am unsure. Remnants of the orginal centre remain in suspension, tumbling within the pale chalcedony like sections of dead leaves. Notice the segregation banding around the edge of the piece.
What also may be sprays of calcite inclusions can be seen around the outer skin. It's interesting that the outer banding in this stone remained intact. From the outside, the agate was highly waterworn, being worn into the central core along one edge.
It's one of my favourite Usan pieces.
I
