70 
Transactions of the Royal Society of South Africa. 
Some of these are no thicker than a visiting card. Macles (for the definition 
of which see any standard work on crystallography) go into this class. 
Mineralogists and crystallographers, outside the diamond trade, commonly 
give the name spinel twins " to macles. The term is not without objection, 
because it is calculated to make the multitude think that a macled diamond 
is really a spinel. It is better to confine the name made," in accordance 
with Kimberley practice, to stones in which the crystallisation has taken 
place right- and left-handed from a common basal plane without inter- 
penetration from either, and to use " twin " for interpenetrating crystals. 
F. Cleavages will be dealt with at some length later on. Here it is 
enough to say that the first five sub-classes — from blue whites to yellows, 
that is — are of good quality, colour, and shape ; whereas the remaining sub- 
classes, from goods to black rejections, are inferior in all ways, and in the 
majority of individuals are spotted. Brown cleavages bear much the same 
relation to brown stones that the first five sub-classes of cleavage bear to 
close goods. 
G-. and H. Rejection Chips and Rubbish are made up entirely of diamonds 
so defective in the requirements of a passable stone that no place can be 
found for them in any of the higher classes lest they spoil the look of the 
whole parcel. They comprise diamonds of all sorts other than true bort — 
the ragtag and bobtail of each. A good quantity of this stuff goes into 
cheap jewellery ; much of it is used for industrial purposes, i. e. for graving 
tools, glaziers' diamonds, and watch pivots. Bultfontein does not produce 
so many small diamonds, averaging, say, a dozen to the carat, as Wesselton 
does, which is one good reason why it has not a class of rejection chips of 
its own. Such rejection chips as it has go into the rubbish. 
I. Bort is mostly converted into powder for grinding and polishing 
purposes. There is a large demand for the best pieces for use in rock drills. 
Notwithstanding that bort only averages 5s. or 6s. a carat, really good " shot 
bort" will fetch as much as<^4 or £5. Some of the distinctive types of bort 
will be described presently. Diamonds not good enough even for the rubbish 
go into this class. 
AA. Close Goods. See the remarks under A. 
BB. Spotted Stones. See C. In sorting Pool or Dutoitspan goods for 
the market, fancies find their best home in this class. 
CC. Flats, here, really contain a few macles ; but most Pool and 
Dutoitspan macles do not harmonise as well with the flats as Wesselton 
and Bultfontein macles do, and so we have a separate class of — 
DD. Macles which are characteristic, in colour and shape, of the former 
mines. They tend to a greenish -grey, are often much spotted, and have, 
with few exceptions, rounded edges sloping outwards (not inwards like 
spinel twins) to the common basal plane. 
EE. Rejection Stones are inferior spotted stones not good enough for BB. 
