Keyshunter is on a track and has very good eyes. Celtic? Probably not in my opinion, but that cross looks like it was definately inlaid with another material.
That is a stunning find.
"On a hill far away stood an old rugged cross,
the emblem of suffering and shame;
and I love that old cross where the dearest and best
for a world of lost sinners was slain.
Refrain:
So I'll cherish the old rugged cross,
till my trophies at last I lay down;
I will cling to the old rugged cross,
and exchange it some day for a crown."