May 30, 1884.] 
FIVE BRAZILIAN DIAMONDS. 
Art the International exposition held at 
Amsterdam during the summer of 1883, was 
exhibited a suite of wonderful round diamonds, 
that, for their size and merit, were awarded the 
prize for ‘round bort.’ They were purchased 
by a New-York firm, who offered them to 
Messrs. Tiffany & Co., and, on examination, 
were found as follows : — 
They are of Brazilian origin, four in num- 
ber, and all as round as marbles. In this form 
they can be used for drilling-purposes to equal- 
ly good advantage with the black amorphous 
carbonado, as the intricate twinning or com- 
pounding destroys the easy cleavage property 
that renders ordinary crystals unfit for this 
purpose. 
No. 1 (fig. 1), the largest diamond, is entirely 
round, of a light vitreous brown color, and trans- 
lucent; its entire surface being covered with 
small re-entering angles, giving it the appear- 
ance of the fibrous, or, rather, bunched crystals 
of acicular rutile, variety nigrine, from Magnet 
Cove, Ark. These markings, numbering hun- 
dreds, are over the entire surface, and render 
it very evident that the crystal is the result of 
a multiplicity of twinnings of cubic crystals, 
as is often the case with iron pyrite. It 
is 17 millimetres in diameter, and weighs 
8.542 grams (413 carats) ; specific gravity is 
3.51954. 
No. 2 (fig. 2) is entirely round, of a milky 
gray color, and translucent. To the eye the 
surface appears quite smooth; but under the 
glass the same markings show, on a smaller 
scale, as in the large diamond, though the sur- 
face is duller. It is 10 millimetres in diameter, 
and weighs 2.0815 grams (1035 carats) ; spe- 
cific gravity is 3.522. 
No. 3 (fig. 3) is almost entirely round, of a 
milky, translucent white, no crystalline mark- 
ings being visible, and has a fused vitreous 
appearance, as if it had been originally round, 
with small pit-markings, and then the entire 
mass fused, thus nearly obliterating the pitting. 
It is 9 millimetres in diameter, and weighs 
1.289 grams (62 carats) ; its specific gravity 
is 3.5218. 
No. 4, the weight of which was 1.478 grams, 
and its specific gravity 3.649, proved, on 
examination, not to be a diamond, but a red 
hematite sphere that had been rolled, and was 
evidently a pseudomorph after limonite or 
some other like mineral, or was filled with air- 
cavities (see low specific gravity). Not com- 
ing into ownership of it, I could only try the 
‘surface, whereas, if it could have been broken, 
SCIENCE. 
649 
more definite results might have been arrived 
at. 
It seems very remarkable, however, that this 
specimen, having been viewed by the majority 
of the Amsterdam diamond-dealers, examined 
by the judges and experts, and then passed 
through the hands of several old and experi- 
enced importers of diamonds, should have 
deceived them all. So perfect was its color 
and lustre, that even a diamond-cutter, when 
informed of the facts in the case, was not con- 
vinced until he had tried the stone on the 
wheel. 
Another curious diamond (figs. 4 and 5) is 
now in possession of Messrs. Tiffany & Co., 
weighing 6%, carats, the original weight of 
which was 104 carats, 4 carats having been lost 
Fie. 2. 
Fi@. 5. 
Fie. 4. 
* 
in cutting. This stone has eighteen facets, of 
which four, of the top and the table, are white, 
and four are a distinct black ; on the back, four 
facets are white, and the other four and the 
culet are black. ‘The stone was found to be 
excessively hard, much above the average of 
hardness, in fact; and, although apparently 
poorly cut, the cutter had sustained a loss, 
owing both to the longer time required in the 
work, and also to the fact that he was remun- 
erated at a certain rate per carat. This dia- 
mond is of Brazilian origin, and was originally 
an octahedron. When found, the entire stone 
was a jet black, and it was cut with the inten- 
tion of producing a black stone. After the 
table had been put on one of the points, and 
the four edges of the octahedron had been 
removed to make four facets, it was found that 
the black color was only a superficial coating, 
and that the inside of the crystal was entirely 
white, with the exception of an occasional car- 
bon inclusion. It shows no more play of color 
than a black stone, but gives very decided 
brilliant metallic reflections. The curious effect 
of five white and four black reflections, and 
the appearance of a clearly defined Greek cross 
in black outline, when viewed by transmitted 
