FLUOR SPAR. - This substance from the confusion in the arrangement, and the frangibility of its crystals requires a peculiar and careful treatment whilst being turned into form, and which is described at page 168-9 of the first volume. The smoothing and polishing are conducted almost the same as in marble, but as fluor spar requires a longer continuance of the polishing process, it demands considerable care to preserve the square fillets of the work from being rounded in the polishing, and with which object the powders are sometimes applied on small square slips of metal or wood, the sides of which are used somewhat as a file so as to present a superior degree of definition and permanence in the form of the polishers, than would be obtained by the exclusive use of cloth applied with the fingers.

The lapidary pursues the same method in polishing fluor spar as carnelian, but he does not succeed so well as the Derbyshire workmen, and only produces what may be termed "a greasy polish."