Visited by Pieter Valkenier

March 30, 1705

Letter L-439 of 25 May 1705 to the Royal Society in London.

At the end of the past month of March Mr Petrus Valkenier came to visit me again; he had with him some crystals, which were still attached to the stones, to show them to me; they were very admirable. Among others, the said gentleman had a fragment the size of a small fist, consisting as it were of small packed-together or joined stones, which were fastened together in a lump by very clear particles, which is given the name of wild crystal. And when one contemplated the so-called crystal particles, the largest elevated points of which were no larger than large grains of sand when viewed through the magnifying glass, it seemed to us that many of them were six-sided and resembled rock crystal.