Laumonite

When I figured the red variety of Zeolite or Stilbite, I had these specimens by me (sent by Mr. G. Don, then gardener at the Edinburgh Botanic Garden, found on his journey from Forfar). They seem to belong to the same rock, but their aspect did not allow me to class them as a variety. Since the able discrimination of Laumonite by the Count de Bournon, I am pleased to show this new variety as a British mineral, as a proof that we are continually discovering substances in our own country that seemed to be only foreign productions. The present specimen does not so readily disintegrate as the foregoing, as it is not so completely changed by exposure to the common air. It has, however, the same form of crystal, and agrees with it in other particulars, and is much coloured by the Red Oxide of Iron. The radiating structure is remarkable in these specimens, and gives them the appearance of Stilbite, but they have not so rich a lustre. These specimens have the phosphorescent Carbonate of Lime (see last page) about them which the foreign specimens have, which has also the diagonal fracture.