A Contribution to the Study of the Diamond Made. 
157 
perfect faces. Oscillation types may have two octahedral faces and three 
rounded edges. Dodecahedral types may have no more than six, or twelve 
usually somewhat arched faces. These last are met with often enough at 
Jagersfontein, and occur also at Wesselton and Bultfontein, where they are 
most common in the smaller sizes. 
Fig. 5. — Made, showing flawed edges. 
The fracture of a made is curious. A smashed diamond crystal, not 
macled, nearly always shows conchoidal fracture dominated by the so-called 
perfect cleavage. But in the case of the made perfect cleavage scarcely 
counts, for it breaks easily enough parallel to an edge, and still more easily 
at right angles to an edge. In the first case the fracture is somewhat 
irregular and conchoidal ; in the second it is remarkably direct, showing, 
moreover, a herring-bone " grain." Many spotted glassy macles have flawed 
Fig. 6. — Herring-bone grain of made. 
edges, the flaws indicating the directions of easy breakage perpendicularly to 
the edges. Fig. 5 depicts a Wesselton made with flawed edges, and Fig. 6 
the grain of a made broken at right angles to an edge.* It may be noted 
here that the straight breakage surface of a made at right angles to an edge 
reveals much better than a natural edge does that the twinning plane is not 
necessarily a true plane at all, but rather an irregular surface, or at best a 
series of small planes on different horizons approximating to parallelism: 
with the triangular faces of the made. 
* See the " Note on the Internal Structure of Diamond," below. 
