DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.1327#0289
290
THE CRYSTAL PALACE AND ITS CONTENTS;
MINING AND METALLURGY.
DIAMONDS AND MINERALS EMPLOYED FOR ORNAMENTAL
PURPOSES.—No. III.
A MONG the minerals employed for personal decoration, the diamond
evidently occupies Hie most prominent position, both on account of Iho
beauty of the gem itself, and also because of its immense commercial value.
Tho diamond, like charcoal, is composed of carbon; and, in a chemical
point of view, differs frOm it only in being period h> free from all traces of
the earthy and other impurities with which the latter substance, even when
most carefully prepared, is to a considerable extent contaminated. This
mineral, although principally used in ornamental jewellery, is likewise'
applicable to many other purposes: in consequence of its extreme hard-
ness it is now extensively employed for making the pivot-boles of the better
description of watches; it has also been used in the formation of holes
through which very Hue metallic wires are drawn, besides furnishing the
only convenient tool which can bs employed for cutting glass.
The countries in which this gem has been yet discovered are far from
numerous, the only localities in which it is found being the Indian peninsula.
Brazil, the island of Borneo, and Siberia, on the western side of the Ural
mountains. Its geological position appears to he among diluvial gravel ami
conglomerate rocks or"end ding-stone, consisting chiefly of rolled (lint pebbles
and ferruginous sand. India lias from the most remote ages been celebrated
for the beauty Slid afflgmtude of its diamond's, the largest and most valu-
able of which
Yisapoor. Tho ti
Comorin to Benga
:s in the provinces of Golconda and
ing these gems extends from Cape
>f a chain of mountains called the
Lp-roclt formation. The diamonds
obtained from* even the richest localities are rarely procured by directly
searchiugthosthda in wiiieh they arc- found, since they are commonly so
coated with an earth v crust on the outside, as not to he readily distinguish-
able from the various other substances with which they are associated.
For this reason the stony matter is first broken into fragments, and then
washed in brains i'er the purpose of separating the loose earth;' after which
tho residual gravel is spread out on a level piece of ground.- whore it is
allowed to dry, and where the diamonds are recognised from their sparkling
in the sun—thus enabling the miners readily to discriminate between them
and tho stony matters with which thev are associated. >.
The chief diamond mines of Brar.it were discovered in the year 1728.
Tho ground hi which they are imbedded exactly resembles that of the
diamond districts of India, and, besides containing fragments of coloured
quart'-! and ferruginous sand, it produces small quantifies oi gold in connec-
tion with oligist iron ore. This conglomerate, or pudding-stone wfucn is
seldom of any great thickness, occur,- at considerable heights in the moun-
tainous table-lauds, and is entirely different from all the other mineral
productions which are to be found in tho vicinity. The principal mine of
this Dart of the world is that of Mamkr-ra, on the river ,%u,ouhouhra, to
the north of B'o Janeiro where the gems are oiiiaiued from tho sand taken
from the bed : t'u: ■ ream, alter laying it nearly dry by drawing off the
water during the dry season into large reservoirs prepared for that purpose.
The "casealho;" or diamond gravel, which is then removed
formed into little heaps or mounds of 13 or 10 tons each
until tho commencement of the rainy season, when it is caref 11 " relflBtt
squaro boxos arranged under large oblong wooden sheds. &-, * Vlu^Hy
works at each of these boxes, and numerous inspectors are plaeJf'r ,VasW
distances among the workmen to prevent any abstraction of ii f"W5
by those who may chance to find them. "When a negro finds ° if&'b
lie immediately shows it to tho inspector, and if its weight amem j Bl°^!
carats, or 70 grains, he receives bis liberty. ' uuls to Vjj
The diamond is found crystallised in the octahedrons form
other immediately derived from it. Its specific gravity varies'f°V m!0!
3'<i. It is not acted upon by any solvent, but, when strongly lie TV'* ^
or oxygen gas, is consumed with the formation of carbonic.'ncid "&
The fracture of this mineral is foliated?—its lamina; beino- nnr li
faces of the regular octahedron. When broken it divides m thed >-° ^
those lines; and this property of the gem is extensively taken ajv , ,j!
by tho lapidary when reducing it to the forms best adapted for omi '"
purposes. ™CQ&
Diamonds are usually colourless and transparent, but when colon
frequently of a yellowish tint. Green diamonds are, nest to veil -a'
most common ; bine specimens are also occasionally found, and alt)" ■
they seldom possess much lustre, are, in many countries, highly \-T^
Of all the coloured varieties the rose or pink diamonds are, howeTCrt
far the most esteemed, aud sometimes even exceed in value' those riV
are perfectly colourless—although, in general, the most liirmid ««„,, '%
be found to bear the highest price. h ™
The art of cutting and polishing tho diamond, although probably horn
in Asia in remote antiquity, was first introduced into Europe bvLmk
Bergher of Bruges, in the year 1-15G. Tho object is effected in two aifev
ways—cither by faking advantage of the natural lamina; of the gem md
splitting itin directions parallel io the faces of the octahedron, or by saina*
it with a very delicate wire covered with diamond powder. By ujk
processes, and more especially by tho former, the diamond is so cut ma
that the weight of the finished gem is rarely more than one-half that of th
rough stone from which it was made; and consequently the value of i
brilliant-cut diamond is considered equal to that of a similar roiHi one £-■■
twice the weight, exclusive of the cost of labour expended in the workman-
ship. The weight and value of diamonds are estimated in carats, of ski;:
150 are equal to one ounce troy, or 480 grains.
The difference between the exchangeable value of two diamonds of eqml
merit is generally estimated in the ratio of the squares of their weights! S3
ttiat the value of three diamonds weighing respectively one, two, and three
Carats, will be as one, four, and
is" estimated at 21. per carat; a
first carat, exclusive of worfem;
uncut diamond of two carats.
The rapidly increasing- value of diamonds in r
in carats, will be readily seen by a glance at tho foil
A wrought diamond of ... 3 carats is
)i .-, 4
The averag
price o
rough dianiDS'i
sequentlv, i
-hen en
, the cost-cf it
will be 8t
which
stlic price of a
100
.-alalia-,;-
of Km
t Sin;
rid. ano '■
d. the K*
Eevond this weight such a motl
applicable, in consequence of the difficulty Of fir
more valuable gems.
OF.the numerous diamonds exhibited, by f(
valuable is the Koh-i-noor, formerly the prop
together with two other specimens of the firs
8 strong cage of gilt iron in the main avenue
property of her Majesty, is one of the lai-gcs
at 2,000",000/. sterling, besides this mognifii
contained a vast collection of jewels of infer
which may be mentioned a unique blue dian:
property of Mr. Hope, which was exhibited i- -■
great lump of gold from California, belonging to the bank of hi
Of the other large diamonds in tho world tho following a
romarkable. That mentioned by Tavornier as belonging to t.
of Mogul, a now extinct kingdom, is said to hi
state I'UO carats ; it was found in the Golconda
and is of the size of a hen's egg divided through
of iis smallest diameter. Among the crown jew
weighing I'lfi eanus ; it is of the sixo of a pigec
the eye of the Brahminical idol Sheriugham. '
Frencli soldier who deserted into the Malabar s
means of purloining the gem; he escaped with i
posed of it for 2,000;. to the captain of a ship, v.
Jew for just six times that amount. Tho Jew suusei
to a Greek merchant, who afterwards sold it to tho li
90,006;. in ready money and an annuity 'of 4,000*.
* For « full ftteouiit of flic Koh-i-noor, see No. 1, p.6; and for 01
eighing 177
>alBsaller
e about the ff
iiiddle'intUen'™
f Russia is a*
o Madra
aftermi
THE CRYSTAL PALACE AND ITS CONTENTS;
MINING AND METALLURGY.
DIAMONDS AND MINERALS EMPLOYED FOR ORNAMENTAL
PURPOSES.—No. III.
A MONG the minerals employed for personal decoration, the diamond
evidently occupies Hie most prominent position, both on account of Iho
beauty of the gem itself, and also because of its immense commercial value.
Tho diamond, like charcoal, is composed of carbon; and, in a chemical
point of view, differs frOm it only in being period h> free from all traces of
the earthy and other impurities with which the latter substance, even when
most carefully prepared, is to a considerable extent contaminated. This
mineral, although principally used in ornamental jewellery, is likewise'
applicable to many other purposes: in consequence of its extreme hard-
ness it is now extensively employed for making the pivot-boles of the better
description of watches; it has also been used in the formation of holes
through which very Hue metallic wires are drawn, besides furnishing the
only convenient tool which can bs employed for cutting glass.
The countries in which this gem has been yet discovered are far from
numerous, the only localities in which it is found being the Indian peninsula.
Brazil, the island of Borneo, and Siberia, on the western side of the Ural
mountains. Its geological position appears to he among diluvial gravel ami
conglomerate rocks or"end ding-stone, consisting chiefly of rolled (lint pebbles
and ferruginous sand. India lias from the most remote ages been celebrated
for the beauty Slid afflgmtude of its diamond's, the largest and most valu-
able of which
Yisapoor. Tho ti
Comorin to Benga
:s in the provinces of Golconda and
ing these gems extends from Cape
>f a chain of mountains called the
Lp-roclt formation. The diamonds
obtained from* even the richest localities are rarely procured by directly
searchiugthosthda in wiiieh they arc- found, since they are commonly so
coated with an earth v crust on the outside, as not to he readily distinguish-
able from the various other substances with which they are associated.
For this reason the stony matter is first broken into fragments, and then
washed in brains i'er the purpose of separating the loose earth;' after which
tho residual gravel is spread out on a level piece of ground.- whore it is
allowed to dry, and where the diamonds are recognised from their sparkling
in the sun—thus enabling the miners readily to discriminate between them
and tho stony matters with which thev are associated. >.
The chief diamond mines of Brar.it were discovered in the year 1728.
Tho ground hi which they are imbedded exactly resembles that of the
diamond districts of India, and, besides containing fragments of coloured
quart'-! and ferruginous sand, it produces small quantifies oi gold in connec-
tion with oligist iron ore. This conglomerate, or pudding-stone wfucn is
seldom of any great thickness, occur,- at considerable heights in the moun-
tainous table-lauds, and is entirely different from all the other mineral
productions which are to be found in tho vicinity. The principal mine of
this Dart of the world is that of Mamkr-ra, on the river ,%u,ouhouhra, to
the north of B'o Janeiro where the gems are oiiiaiued from tho sand taken
from the bed : t'u: ■ ream, alter laying it nearly dry by drawing off the
water during the dry season into large reservoirs prepared for that purpose.
The "casealho;" or diamond gravel, which is then removed
formed into little heaps or mounds of 13 or 10 tons each
until tho commencement of the rainy season, when it is caref 11 " relflBtt
squaro boxos arranged under large oblong wooden sheds. &-, * Vlu^Hy
works at each of these boxes, and numerous inspectors are plaeJf'r ,VasW
distances among the workmen to prevent any abstraction of ii f"W5
by those who may chance to find them. "When a negro finds ° if&'b
lie immediately shows it to tho inspector, and if its weight amem j Bl°^!
carats, or 70 grains, he receives bis liberty. ' uuls to Vjj
The diamond is found crystallised in the octahedrons form
other immediately derived from it. Its specific gravity varies'f°V m!0!
3'<i. It is not acted upon by any solvent, but, when strongly lie TV'* ^
or oxygen gas, is consumed with the formation of carbonic.'ncid "&
The fracture of this mineral is foliated?—its lamina; beino- nnr li
faces of the regular octahedron. When broken it divides m thed >-° ^
those lines; and this property of the gem is extensively taken ajv , ,j!
by tho lapidary when reducing it to the forms best adapted for omi '"
purposes. ™CQ&
Diamonds are usually colourless and transparent, but when colon
frequently of a yellowish tint. Green diamonds are, nest to veil -a'
most common ; bine specimens are also occasionally found, and alt)" ■
they seldom possess much lustre, are, in many countries, highly \-T^
Of all the coloured varieties the rose or pink diamonds are, howeTCrt
far the most esteemed, aud sometimes even exceed in value' those riV
are perfectly colourless—although, in general, the most liirmid ««„,, '%
be found to bear the highest price. h ™
The art of cutting and polishing tho diamond, although probably horn
in Asia in remote antiquity, was first introduced into Europe bvLmk
Bergher of Bruges, in the year 1-15G. Tho object is effected in two aifev
ways—cither by faking advantage of the natural lamina; of the gem md
splitting itin directions parallel io the faces of the octahedron, or by saina*
it with a very delicate wire covered with diamond powder. By ujk
processes, and more especially by tho former, the diamond is so cut ma
that the weight of the finished gem is rarely more than one-half that of th
rough stone from which it was made; and consequently the value of i
brilliant-cut diamond is considered equal to that of a similar roiHi one £-■■
twice the weight, exclusive of the cost of labour expended in the workman-
ship. The weight and value of diamonds are estimated in carats, of ski;:
150 are equal to one ounce troy, or 480 grains.
The difference between the exchangeable value of two diamonds of eqml
merit is generally estimated in the ratio of the squares of their weights! S3
ttiat the value of three diamonds weighing respectively one, two, and three
Carats, will be as one, four, and
is" estimated at 21. per carat; a
first carat, exclusive of worfem;
uncut diamond of two carats.
The rapidly increasing- value of diamonds in r
in carats, will be readily seen by a glance at tho foil
A wrought diamond of ... 3 carats is
)i .-, 4
The averag
price o
rough dianiDS'i
sequentlv, i
-hen en
, the cost-cf it
will be 8t
which
stlic price of a
100
.-alalia-,;-
of Km
t Sin;
rid. ano '■
d. the K*
Eevond this weight such a motl
applicable, in consequence of the difficulty Of fir
more valuable gems.
OF.the numerous diamonds exhibited, by f(
valuable is the Koh-i-noor, formerly the prop
together with two other specimens of the firs
8 strong cage of gilt iron in the main avenue
property of her Majesty, is one of the lai-gcs
at 2,000",000/. sterling, besides this mognifii
contained a vast collection of jewels of infer
which may be mentioned a unique blue dian:
property of Mr. Hope, which was exhibited i- -■
great lump of gold from California, belonging to the bank of hi
Of the other large diamonds in tho world tho following a
romarkable. That mentioned by Tavornier as belonging to t.
of Mogul, a now extinct kingdom, is said to hi
state I'UO carats ; it was found in the Golconda
and is of the size of a hen's egg divided through
of iis smallest diameter. Among the crown jew
weighing I'lfi eanus ; it is of the sixo of a pigec
the eye of the Brahminical idol Sheriugham. '
Frencli soldier who deserted into the Malabar s
means of purloining the gem; he escaped with i
posed of it for 2,000;. to the captain of a ship, v.
Jew for just six times that amount. Tho Jew suusei
to a Greek merchant, who afterwards sold it to tho li
90,006;. in ready money and an annuity 'of 4,000*.
* For « full ftteouiit of flic Koh-i-noor, see No. 1, p.6; and for 01
eighing 177
>alBsaller
e about the ff
iiiddle'intUen'™
f Russia is a*
o Madra
aftermi