126 Ichikawa — Xotes on Japanese Minerals. 



elevations formed by etching ; the striations on the faces 

 mRn, etc., also are formed by etching, and the striations 

 are parallel to the direction of cleavage. 



Fig. 2 (A) shows a crystal strongly etched; the pyra- 

 mid is rounded and has numerous new forms like an 

 acute trigonal pyramid on its surface ; this new form is 

 similar to C of figure 4 (this Journal, vol. 42, pp. 114, 

 1916), but the former is a front view and the latter is 

 drawn in perspective. B shows the relation between the 

 outline of the top of the new form and the edges of the 

 original crystal in a horizontal projection. 



Fig. 3 shows the etching of a prismatic crystal. A is 

 a front view; B shows a V-shaped figure (abc) on the 

 face mR and the arrangement of the trigonal pits ; C is 

 a trigonal pit on the face p; D and E show varieties of 

 natural raits on the face mR. The angles are: A, B, C 

 (abc)=100°;D,E(abc)=70°; D(dbe)=100°. 



Fig. 4 is a prismatic crystal with mR, A is a front 

 view (X 5) ; B shows striations and pits on the face mR 

 deeply etched. The base of the pit is parallel to the 

 cleavage, and the angle abc = 145°. C, D, E, etc. show 

 varieties of natural pits on the face mR; the angles 

 are C, D, E(abc)=75°; E(doe)=105°; E(bcd)=100 = . 

 Fig. 5 shows etchings in a prismatic crystal with dihex- 

 agonal prism (<«Pw) (X 5). Striations of AB, BC, etc. 

 on the prism are parallel to the direction of cleavage; 

 abc = 145°. 



On the second page of the figures (II), figure 1 shows a 

 short prismatic crystal from a crystalline limestone at 

 Kamiomushi, Echizen Province. Rhombic plates on the 

 face — y 2 R and trigonal plates on the face mR are new 

 faces formed by etching. Cross striations on the faces 

 — ] ._>R and^i? show the direction of cleavage. The crys- 

 tal is nearly opaque and has a transparent greenish 

 coating, but the face R looks almost white being formed 

 by innumerable rhombic etching planes (D). A is a 

 front view (X10) ; B shows an elevation formed on the 

 face — V 2 R in horizontal projection: the three rhombic 

 planes are new faces of a rhombohedron formed by etch- 

 ing. C shows an elevation produced on a trihedral angle 

 (a in A) formed by the combination of the faces — V 2 R 

 and *> R ; D shows a group of rhombic plates formed on 

 the face « R ; E, F, G, etc, show trigonal plates formed 

 on the face mR and varieties of natural pits formed 



