Spodumene and its Alterations. 329 



tween micaceous and fibrous, with a strong wavy tendency of 

 the foliation, on the surface of fracture, especially in the thicker 

 crusts with longer fibres. In the smaller crystals, the plane of 

 foliation is usually at right angles to the faces of the Spodu- 

 mene, and the folia therefore radiate from a central plane in 

 those crystals which are completely altered ; but in the larger 

 ones, within a thin radiating crust of this kind, the folia of 

 the psendomorph generally and mainly conform to the central 

 plane — that of the orthocliagonal cleavage of the Spodumene, — 

 and a parallel foliation often results, with a complete disap- 

 pearance of the wavy tendency along the axis of the pseudo- 

 morph. When a core remains in the smaller crystals, it is very 

 often, if not generally, found to consist of the blackish-green 

 Finite (Killinite), while in the larger crystals the core consists 

 of bright-green to greenish- white or white Spodnmene, often 

 with the dark Pinite within an inch or so of its termination, or 

 forming a thin layer at various places next to the white pseudo- 

 morphous crust. Most of these phenomena are shown in Fig. 1, 

 Plate XIII, a sketch (natural size) of the cross-fracture of one of 

 the partially altered crystals. In this, a rem nant of unaltered Spo- 

 dumene is presented in the dark core, of a greenish-grey color, 

 retaining the three cleavages indicated by the lines, and bor- 

 dered, especially near the lower angle of the core, by a thin 

 film of blackish-green Killinite. The whole is enveloped by the 

 crust of wavy white Cymatolite, with satiny lustre, which also 

 traverses the core in thin seams. 



The greenish -yellow Muscovite, which abounds in the vein, is 

 commonly intercrystallized in the larger pseudomorphs, in scales 

 and films, sometimes so intimately that the two materials are 

 indistinguishable by the eye, and a yellowish color is produced. 

 The more slender of the pseudomorphous crystals are often 

 found penetrating the coarse masses of Beryl, but the latter is 

 never enclosed ; while the black octahedra of Oerstedite are fre- 

 quently found, not only implanted on the outer planes of these 

 pseudomorphs, but often enclosed in the above yellow mixture. 

 Many of the longer pseudomorphous prisms are fonnd to be 

 more or less flattened, distorted, twisted, or bent into decided 

 arcs, or with their terminations squeezed into a wedge or bladed 

 shape. At this locality there is a remarkable want of adherence 



