. The Canadian journal of industry, science and art. ON THE KLAPROTHINE OR LAZULITE OF NORTH CAROLINA. 365 upon these Lazulite crystals as Trimetric combinations, hemihedrally modified. From my examination of the North Carolina specimens, I cannot but think that this view will in the end prevail. It is supported by the fact that in many combinations the upper and lower forms do actually correspond in number and character ; and that practised crystallographers like Phillips and Levy, skilled in the use of the goniometer, were unable to detect in their measurements the differences announced by P
. The Canadian journal of industry, science and art. ON THE KLAPROTHINE OR LAZULITE OF NORTH CAROLINA. 365 upon these Lazulite crystals as Trimetric combinations, hemihedrally modified. From my examination of the North Carolina specimens, I cannot but think that this view will in the end prevail. It is supported by the fact that in many combinations the upper and lower forms do actually correspond in number and character ; and that practised crystallographers like Phillips and Levy, skilled in the use of the goniometer, were unable to detect in their measurements the differences announced by Priifer.* The North Carolina crystals—presuming those in my possession to represent the generality of crystals obtained at this locality—although usually distorted, are of an extreme simplicity : contrasting remark- ably in this respect with the majority of European examples. At first sight, they resemble a monoclinic prism terminated by a single "augite-pair" or hemi-pyramid; but they really consist (if monoclinic) of two hemi-pyramids, the four planes of one of which are greatly elongated; or, if trimetric (as I conceive them to be), they form a rhombic octahedron in which four planes, in opposite sets of two, are thus lengthened beyond the others. Fig. 1 represents this distorted aspect; Fig. 2, the same form (or combination, if monoclinic) in symmetrical proportions. These sym- metrical crystals are of smaller size, and less numerous, than the distorted forms. Although the edges of these crystals are sharply defined, the planes are unfortunately without lustre. The most careful measurements of five crystals, by means of a fixed or Adelmann's goniometer gave me the same angles for both the upper and lower faces. The difference found by Priifer is too slight, how- ever, to be satisfactorily detected by any kind of application goniometer. I attached, therefore, thin films of mica as carefully as possible to the planes of one of the crystals, and measured the angle
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