Note on Francolite

Extract

Some little confusion having apparently arisen with respect to the characters of certain Cornish apatites, it may be well in the interests of scientific exactitude to point out the following facts. —In a series of specimens of Franeolite from Fowey Consols one may observe every gradation of form betwixt long and coarsely striated hexagonal prisms and narrow-edged crystals of an almost lenticular shape. Similar to the latter in their small vertical measurement are the "thin hexagonal plates" which have been enumerated among the known varieties of Cornish apatite, and which are, indeed, indistinguishable in general characters from the recently described Francolite of Levant Mine, St. Just. The particular Francolite, however, which, obtained by Mr. Talling from Fowey Consols, was shown by Maskelyne and Flight to contain over 5 per cent. of calcium carbonate (Journ. Chem. Soc. Jan. 1871), must not be identified with any one of the three varieties just mentioned.