E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Carbuncle of Ward Hill (The).
A mysterious carbuncle visible enough to those who stand at the foot of the hill in May, June or July; but never beheld by anyone who has succeeded in reaching the hill top.
I have distinguished, among the dark rocks, that wonderful carbuncle, which gleams ruddy as a furnace to them who view it from beneath, but has ever become invisible to him whose daring foot has scaled the precipice from which it darts its splendour,Sir W. Scott: The Pirate, chap. xix.
Dr. Wallace thinks it is water trickling from a rock, and reddened by the sun.