Brittany

.. the large celt appears to have been fixed in a cleft stick, or enclosed within the folds of a tough, slender branch [..] It is said that when the Breton peasant finds a celt, called in most countries on the Continent a "thunderstone," he places it in the cleft of a growing branch or sapling, and leaves it there until the wood has formed and hardened round it; but this must have taken a great length of time. We do not, however, find the slightest trace or mark of such a handle on a single celt in this Collection [that of the Museum of the Royal Irish Academy].