Page:A treatise on diamonds and precious stones including their history Natural and commercial.djvu/155

 the alluvium, and may be said to be generally distributed in all parts of the world. Small pebbles of crystal are often collected in the vicinity of London, as Bagshot, &c.. which, on account of their cutting glass, and shining when polished, are called diamonds.—We have also Irish and Cornish diamonds belonging to the same class.

receives a good polish, and is worked into an immense variety of forms; it is much used in jewellery, and commonly set on foil. Larger pieces are cut for the glasses of spectacles, hence called Pebble Spectacles. It is a substance in very general demand, and sells at from two shillings to ten shillings per pound.

THE CAT'S EYE

considered to be a variety of crystal, enveloping amianthus.