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different kinds of stones are used as tovich-stones, schistus, schistose
jaspers, and perhaps even basalts. Wallerius thought he distin-
guished three kinds of touch-stones, which he referred to three kinds
of rocks, basalt, schistus, and corneenne"



MODE VII. SAUSSURITE.



the goldsmiths and assayers of Paris. I have
seen no other sort among them. It is so much
the better, as it is blacker, and more compact.
It is certainly,, properly speaking, neither a ba-
salt nor a schistose jasper. It is said to come
from Germany, by the way of Nuremberg : but
those who sell them know nothing more of it.

<c Corneenne belongs either to primitive or
transitive earths. It never contains organised
fossile bodies. Sometimes it forms thick beds,
sometimes it presents itself in masses, in which
the stratification is not perceptible. It consti-
tutes in this instance the base of certain amyg-
daloids, or glandular rocks."*

Brochant is equally perplexed. The come-
enne, he says, is sometimes siliceous schistus,
sometimes Lydian stone, sometimes the clay-
slate of Werner, hornblende slate, wacken, trap.
An Appellation so vague ought to be finally dis-
missed. The other pierres de come of the French
will be found in their proper divisions ; but as
that analysed by Saussure himself contained
magnesia, which rarely occurs in the stones
above mentioned, it is proper to confine his
illustrious name to the present division, which
has scarcely attracted the notice of mineralo-

* Brongniart, i. 550.



DOMAIN IV. TALCOUS.



gists. Mr. Kirwan has indeed observed, that
serpentine is sometimes intimately mixed with
hornblende, or trap, in which case it is black.
It may in that case be regarded as a transition
from serpentine to Saussurite; and the connec-
tion between trap and serpentine has been al-
ready observed by Werner.

Saussurite, in rolled pebbles, from the lake of
Geneva.

The same, from the Alps.

Saussurite, with nodules of steatite, from the
western isles of Scotland.

With veins of amianthus, from the Pyrenees.

This substance is common in Saussurite, and
evinces its magnesian nature.



MODE VIII. GREEN GRANITEL.

A genuine green granite, found -among the
ancient monuments of Egypt, has already been
described in the account of that rock ; but that
beautiful substance is so extremely rare, that it
cannot interfere with the present object. The
Egyptian is composed of quartz, mica, and an
ofVosges. emerald green felspar; while the green granitel
here implied seems a mixture of felspar and si-
derite with steatite, the magnesia having even



MODE IX. MAGNESIAN LIMESTONE.

penetrated the felspar, and imparted its usual
green colour, whence it has received its common
appellation.

It is found in the Vosges mountains in France,
and there is a manufactory at Paris, where it is
cut into tables, vases, chimney-pieces, and other
articles of decoration.

The fracture has the soft unctuous appear-
ance of a magnesian rock, and the obscure green
colour is a further characteristic of that class of
stones, so that there seems little doubt but it
must belong to this Domain.

Similar granitels are found, it is believed, in
Westmoreland, and in Ireland. Occasionally
some crystals of the felspar are large and regu-
lar, when it assumes the form of a porphyry.



MODE IX. MAGNESIAN LIMESTONE.

Many limestones are so much impregnated
with magnesia, that their qualities become al-
tered, and they are injurious to vegetation.
According to Dr. Kidd, the limestone of parts
of Derbyshire, Nottinghamshire, and Yorkshire,
is of this kind; and at Matlock the limestone
of the rocks on the side of the river where the
houses are built is magnesian 5 on the other






364 DOMAIN IV. TALCOUS.

pure. Mr. Tennant has analysed the stone em-
ployed in two remarkable ancient buildings.



" STONE OF YORK
MINSTER.

Carbonic acid . 47,00

Lime 33,24

Magnesia . . . 19,36
Iron and clay . 0,40

100,00



" STONE OF WESTMIN-
STER HALL.

Carbonic acid . 47,16

Lime 33,48

Magnesia . . . 17,76
Iron and clay . 1,60

100,00"



But the most remarkable stone of this kind is
Dolomite. Dolomite, resembling a primitive granular lime-
stone, but which, according to many analyses,
contains not less than 45 of magnesia, in the
form of carbonate. This stone received its name
from Dolomieu, who observed it among the
remains of ancient sculpture at Rome; and after-
wards discovered it in the mountains of Tyrol.
It has been classed among the primitive mar-
bles; but the essential difference is, that the in-
fluence of the magnesia prevents its effervescence
with acids, unless previously pulverised, when
the calcareous particles are affected by the ex-
posure. It is also sometimes phosphorescent
when scraped in the dark, and elastic in thin
plates. It sometimes contains veins of green
mica, like the primitive marble called Cipolino.
In appearance it differs but little from granular



MODE IX. MAGNESIAN LIMESTONE.

limestone. The Apollo of Belvidere, and some
other beautiful statues, are said to be formed of
Dolomite.

Dolomite forms arrects, or uprights, extend-
ing from the base to the summit of the Alps of
Tyrol ; whence it has become a proverb in the
country, that no mountain exists without a hat
of limestone*. It is sometimes in large masses,
sometimes in thin layers, alternating with foli-
aceous mica. Saussure, 1929, observes, that
most of the primitive limestones of St. Gothard
are Dolomites ; and they often contain the para-
sitic substance called tremolite.

STRUCTURE I. MAGNESIAN LIMESTONE.

From the North of England, and various other
countries.

STRUCTURE II. DOLOMITE.

Aspect 1. Entire. From the ruins of Rome.
From the Alps of Tyrol.

Aspect 2. Mingled. From St. Gothard, with
tremolite.

The same, elastic, with foliaceous mica,

* Patrin, ii. 30Q,



S66 DOMAIS IV. TALCOU5.



MODE X. GREEN MARBLE.

In most rocks the green colour betrays the
presence of magnesia, whence it becomes an
emphatic epithet. In the magnesian limestone
this effect is not observable, because the minute
talcous particles are intimately combined with
the calcareous - y but where they are aggregated
apart, as in the green granitel and green marble,
the colour becomes characteristic. The latter
is also called sometimes serpentine marble, be-
cause in fact the green parts belong to the rock
called serpentine, while the white are purely
calcareous. These marbles have never been
classed with glutenites, being neither bricias nor
pudding-stones, but an irregular and original
compound of serpentine and marble, in which
the former is preponderant.

The most celebrated rock of this description
is that called the verde-antico, or ancient green,
in which a green serpentine with dark spots,
seemingly rather argillaceous, is interspersed
with a pure white marble. This is the Laconian
marble of the ancients, of which there were
quarries near Mount Taygetus; and Pliny has
rightly characterised it as more cheerful than




MODfe X. GREEN MARBLfe.

any other. But the whole passage again de-
serves attention : " Some marbles are esteemed
VERY PRECIOUS, as the Lacedemonian green,
more cheerful than all the rest. So ALSO the
Augustean, and afterwards -the Tiberian, first
discovered in Egypt in the reigns of Augustus
and Tiberius. The difference between them and
ophites is, that the latter is spotted like a ser-
pent, whence it received the name; while the
others present spots of a different form, the
Augustean being crisped into wavy spots, while
in the Tiberian the white (canitics} is scattered,
not convolved.*'

Such is this celebrated passage, which has led
to many errors in mineralogy, as it has been
conceived that the ophites was green porphyry,
and that the other kinds were green; whereas it
is clear from the subsequent part of Pliny's de-
scription, that the ophites was grey or whitish,
being a spotted ollite, and when the spots were
of golden mica it became the most esteemed
Lapis Thebaicus of the ancients. In like man-
ner the " sic 9 so the Augustean," only implies
that both were esteemed very precious, like the
Laconian, but not that they were of a green
colour*.

* For the ancient testimonies concerning the green marble of
conia, the reader is referred to the learned work of Blasius Gary-



368 DOMAIN IV. TALCOVS.

A recent French author gives the following
account of the verde-antico ; but he is certainly
mistaken when he regards it as a bricia.

" The verde-antico should be considered as a
kind of bricia, the paste of which is a mixture of
talc and limestone, and the fragments, of a
greenish black, are owing to serpentine more or
less pure. This marble is an aggregate of white
marble and green serpentine, reduced to angular
pieces, or blended in its paste, and giving to it a
green colour, more or less deep.

" The verde-antico marble of the finest quality
is that of which the paste is of a grass green,
and the black spots are of serpentine, of that
sort called noble serpentine. It should also be
sprinkled with white spots, which renders it
more gay than when they are wanting.

" This marble is much esteemed in commerce,
but large pieces of a fine quality are seldom
found. Nevertheless there are four beautiful
columns in the Hall of Laocoon, in the Napo-
leon Museum ; but there are much finer ones at
Parma.

" It was known by the ancients under the
name of Sparta?ium, or Lacedtzmonium ; and 'we

ophilus (Biagio Garofalo) De Marmorilus Antiquis. Traj. 1743,
4to. Some extracts may be found in the Appendix. See also the
account of the ancient marbles in Domain V.






MODE X. GREEN MARBLE. 369

are informed it was dug in the environs of Thes-
salonica, in Macedonia, which at present forms
part of European Turkey*.

" This verde-antico a properly so called, must
not be confounded with the marbles known by
the names of vert-de-mer, orvert-d'Egypte. The
real verde^antico is a bricia, and never is mingled
with red spots, while those just mentioned are
veined marbles, mixed with a dull red substance
which gives them a brownish hue, not very
agreeable. Besides, it is one of those marbles
which decompose in the open air."f

This decomposition is rather a proof that the
darkest parts are of an argillaceous nature. Dr.
Kidd regards the genuine verde-antico,> which
must be carefully distinguished from ancient
green porphyry* and from mere serpentine, as
" an irregular breccia, consisting of fragments
of dark grey compact limestone, black argilla-
ceous schistus, and white granular marble, im-
bedded in a species of serpentine, which here
and there is of a uniformly green colour, and a
considerable degree of transparency, very closely
resembling jad, or compact talc.

" The fragments of white marble are very sin-
gularly fringed, as it were, with H green sub-

* A gross mistake, and glaring inconsistency,
t Brard, 333.
VOL. I. 2 P.



370 DOMAIN IV. TALCOUS.

stance, which, proceeding in the form of close
parallel fibres from every part of the edge, pene-
trates into each fragment to the extent of about
the tenth of an inch.

" This appearance is of difficult explanation;
because it seems that the penetration, being so
regular, and accommodated to the outline of the
fragment, must have taken place subsequently
to the formation of the breccia/*

It is certain that different specimens of this
substance have great variations, as probably
they are from different quarries. In some the
pieces of clay-slate easily detach themselves
from the mass ; but in the finest fragments the
whole is so intimately blended together, and the
general appearance so different from that of a
bricia, that no artist nor antiquary has ever ap-
plied this name to the Spartan green. Parts of
the new quarry in the Isle of Anglesea perfectly
resemble the verde-antico ; but no one has sup-
posed that beautiful stone to be a bricia. The
poize vera of Genoa is in like manner a green
serpentine, with veins of white marble, but is
never classed among the bricias.
others, There is another ancient and very rare mar-

Antique.

ble, of a deep green, with little distant red and
black spots, and fragments of entrochi changed
into white marble. Another rare kind is called



MODE X. GHEEN MARBLE.

leek marble, being of a bright green, shaded
with a blackish green, so as to form long veins,
with a fracture in splinters like that of wood.
There is a table of it at the Hotel de la Moii-
noie, at Paris*.

Of modern green marbles, the polzevera, al- Modem,

Polzevera,

ready mentioned, is so called from a mountain
on the north of Genoa. This marble often pre-
sents red calcareous parts f, like that of Angle-
sea; but in the latter the red, and even the
white, seem so intimately combined with mag-
nesian particles, thai they do not effervesce with
the nitrous acid, while in the verde-antico the
effervescence of the white parts is very strong.
The polzevera is common in ancient chimney-
pieces, both in France and England, for exam- .
pie, in the British Museum. There is also a
green and white marble, found at Suza, in Pied-
mont.

The green marble of Campan, and other dis- of Campan,
tricts of the Pyrenees, also consists of limestone
mixed with talc; but the structure is so singu-
lar, that it is classed among the Anomalous
Rocks. The Isle of Elba also presents a white
marble, veined with dark green; but the green
marbles of Florence seem strictly to belong to

* Brard, 335.

t So our author, but the red seem serpentine.

2 B 2



372 DOMAIN IV. TALCOUS.

serpentine, as probably does the bisachino of
Sicily. A green marble, resembling the verde-
anticoy is also found at Grenada, in Spain.

What is called at Paris marbre cTEcosse is a
serpentine, from Portsoy. But one of the most
beautiful green marbles yet discovered is that of
Of Angiesea. Anglesea, which sometimes resembles the verde-
antico; in other parts is interlaced with rose-
coloured veins 3 and in others variegated with
red and green of dissimilar intensity. It would
appear, as already mentioned, that even the cal-
careous parts are much impregnated with mag-
nesia, or, in other words, are Dolomite. This
marble was long since described by Da Costa,
and latterly by Coquebert.



MODE XL MAGNESIAN INTRITE.

Serpentine The chief rocks of this description hitherto

porphyry.

observed, are what have been called pot-stone
and serpentine porphyries, the latter being found
near Florence. The base is of the usual colours
of these two substances, interspersed with larger
or smaller crystals of felspar.

Magnesian intrites also exist with crystals of
quartz, or calcareous spar.

To this Mode may be referred the following
rocks, described by Saussure :



MODE XII. MAGNESIAN GLUTENITE. 373

A steatitic rock, with crystals of rose-co-
loured felspar. 154.

He describes, 1437, what he calls a serpen-
tine porphyry, but really an intrite with small
crystals of actinote.

A hard green serpentine, with spangles of a
brighter green, semi-transparent, and resembling
wax ; being seemingly a secretion, or confused
crystallisation, of the purest parts of the stone.
May not the same remark be applied to porphy-
ries, &c. ? 959.

Steatite, crystallised in ollite, the crystals be-
ing laminar, and of a grey inclining to green.




MODE XII. MAGNESIAN GLUTENITE.

This Mode presents, as usual, two Structures,
the large and the small grained.

STRUCTURE I. LARGE-GRAINED.

%

A late ingenious writer gives the following ac-
count of two curious magnesian bricias, the latter
however being more strictly a pudding-stone.

<f 1. Steatitic bricia of Corsica. This bricia,
the steatitic base of which is of a reddish white,
contains fragments of the same substance, which



374 DOMAIN IV. TALCOUS.

are angular, in general small, some of which are
of a blood red, and others of a grass green. This
beautiful rock, which resembles in its paste the
rock called lard-stone, used by the Chinese, was
discovered by M. Rampasse in Corsica, in the
department of Golo. I could have wished to have
given it a more exact locality, on account that it
would be highly interesting to work this beautiful
steatitic bricia : but M. Rampasse constantly re-
fused it.

" 2. Steatitic bricia of Monte Nero. The
steatitic bricia of Monte Nero is found in the lit-
tle torrent of Orsara, in Liguria. Instead of a
base wholly talcous, like the preceding, it consists
of a calcareous base of a cherry red, with a gra-
nular and scaly fracture, and only its spots are
owing partly to pebbles of serpentine of a pista-
chio green, and partly to some globules of laminar
diallage. It sometimes happens that the spots of
serpentine are surrounded with white rings, which
farther relieves the richness of this beautiful bri-
cia, which was discovered by M. Viviani, a learned
mineralogist*. It is to be regretted that its site
is not yet known, it being only found in detached
masses, in the torrent of Orsara. "f

Mr. Kirwan mentions among the bricias the

" * Viviani, Voyage in the Apennines of Liguria, p. 16."
t Brard, 482.



MODE XII. MAGNESIAN GLUTEN1TE. 375

telgsten of Cronstedt, consisting of indurated
steatite, mixed with micarel, or felspar, or schorl,
or tourmaline ; but this is rather a mingled mag-
nesian rock, as is the serpentine, interspersed with
quartz, mica, limestone, or garnets.

Some authors, as already stated, regard the
verde-antico as a bricia.

STRUCTURE II. SMALL-GRAINED.

These have scarcely been observed*.

* Perhaps the rag-stone of Da Costa, p. 173, is of this kind,
being of a greenish grey, and of a talcous appearance. It is used as
a hone to give a fine edge.





DOMAIN V,

CALCAREOUS.



CALCAREOUS EARTH.

A HIS important substance is produced
by burning limestone, marble, or chalk ;
and is commonly known by the name of
lime. The purest is yielded by calcareous
spar, or some white marbles.

Its taste is hot and acrid ; and it is inca-
pable of fusion, even by the burning-glass.



DOMAIN V. PALCAREOUS. 377

I

It may however be fused when joined with
silex or clay.

Limestone is composed of lime and car-
bonic acid. Heat separates the latter, and
the lime is left pure. This acid is a spe-
cies of gas, formerly called fixed air, and
discovered by Dr. Black in 1756; an event
which formed a revolution in the history
of chemistry. Atmospheric air is composed
of about seventy-four parts in the hundred
of nitrogen, and twenty-six of oxygen :
but the latter varies; and there is com-
monly one in the hundred of carbonic acid
gas. Hence lime exposed to the air ab-
sorbs the carbonic acid, and may again
become a carbonate, or limestone.

In architecture, mortar is composed of
quick lime and sand; and when mixed
with a proportion of iron, or manganese, it
.becomes extremely hard, even under water.

When combined with sulphuric acid, the
calcareous earth forms gypsum, or selenite,
which being burnt produces what is called
plaister of Paris. The alabaster of the mo-
derns commonly belongs to the same com-



378 DOMAIN V. CALCAREOUS.

bination ; while that of the ancients is often
a stalagmite, or secretion of common lime-
stone. With fluoric acid, calcareous earth
becomes fluor, or fluate of lime.

The greater proportion of limestone is
produced by the decomposition of marine
shells ; but the more ancient, which is crys-
tallised, and presents no trace of such re-
mains, is called primitive, being supposed
as ancient as any of the rocks. It is in
general easily distinguished from the other
substances by the nitrous acid, formerly
called aqua-fortis, which excites efferve-
scence; but when mixed with magnesia, or
much silex, this effect is slowly procured.
Nor do gypsum nor fluor effervesce.

To these observations, which are chiefly
extracted from Kirwan, Thomson, and Pa-
trin, it may be added that, in 3808, Mr.
Davy reduced lime to a metal, which had
the colour and lustre of silver, and burnt
with an intense white light into quick lime.

In some works of mineralogy the first
three Modes of this Domain, and even the
three succeeding, have been arranged as



DOMAIN V. CALCAREOUS.



mere sub-species, or varieties of limestone.
Strict chemical analysis may probably dis-
cover a different proportion of ingredients,
as, for examples, more water of crystallisa-
tion in marble, and more or less silex or
argil ; and there is at any rate a difference
in the mode of combination. But the chief
use of any system being to assist the me-
mory, even the strict precision of terms
becomes mere pedantry, if it be not sub-
servient to this main object. Too large
masses of colour, or too small, will render
the picture equally inelegant and obscure.



DOMAIN V. CALCAREOUS.



MODE I. MARBLE.

Texture, large or small grained, generally in
distinct concretions ; sometimes so fine grained
as to appear compact, and only distinguishable
by its glimmering lustre : admitting a fine polish.

Hardness, of course marmoric. Fracture, fo-
liated. Fragments, amorphous, blunt.

Weight, granitose.

Lustre, from glimmering to shining ; between
pearly and vitreous. Somewhat translucent, but
the black only on the edges.

It chiefly consists of about 50 lime, and 40
carbonic acid ; whence it is called by chemists
a carbonate of lime.

The most common colours are white and
black ; but the others are so numerous, that they
may be best observed in the subsequent enume-
rations of various kinds of marble.

For the geognostic relations of this celebrated
rock, the reader is referred to Mode III., where,
in treating common limestone, a wider field of
observation maybe opened.

Mineralogists have sometimes regarded those
marbles as primitive which present what they
call a granular fracture, of a shining or saline



MODE I. MARBLE. 381

appearance; while those with a dull earthy frac-
ture were regarded as secondary. But Brard
has well observed, that a true white saline sta-
tuary marble, presenting every character of the
primitive, may be of very recent formation, as
appears from the constant depositions of the
waters of St. Philip, in Tuscany, and of several
other regions. Marbles of an earthy fracture
have been found even among those esteemed the
most primitive of the Alps.

Marble is distinguished from limestone by
superior weight, and by superior hardness and
compactness, so that it assumes a brighter po-
lish. But many of the alabasters will scratch
marble, being of course of a still harder nature.

While the Egyptians often employed the eter- Use in

& J r J architecture.

nal granite, the Greek and Roman architects,
who required greater roundness and softness
of forms, chiefly used marble, as more easily
wrought, and likewise more abundant in their
countries. Nor does its duration seem much
inferior to that of granite, or porphyry, when,
sufficiently pure and unmixed with argil ; for
not to mention the beautiful statues (which are
often under shelter), ancient temples have suf-
fered more from the hand of bigotry or bar-
barism than from the lapse of time. Marble is
however exposed to accidents which could not






382 DOMAIN V. CALCAREOUS.

affect granite, or porphyry. A singular

T Serap?s. f P^ e occurs m tne rums f tne temple of Serapis,
on the delicious coast of Baias, where three
large columns of Cipoline marble are pierced
by pholades, a kind of sea snail, which penetrate
deep holes into limestone, whence they are ex-
tracted, and called sea-dates, being a luxury of
the Italian repast*. These perforations extend
to not less than sixteen feet above the level of
the sea ; whence some have argued that the lat-
ter has subsided, while others suppose that the
land has been raised by earthquakes. A more
probable and easy solution would be, that these
columns have belonged to some more ancient
edifice, which may have been ruined by an
earthquake, and fallen into the sea; or the ship
which conveyed them may have been wrecked ;
or, in fine, the pillars left partly within the sea
.mark for a certain space of time. For in this
very temple, the Pentelican marble of Attica,
and the African bricia, occur; and it is well
known, from many examples, that the Romans
transported obelisks and columns from many
countries, to adorn Italy.

Primitive. The celebrated Buffon had advanced an opi-
nion, that all calcareous rocks were mere re-

* Breislak, ii. 163.



MODE I. MARBLE.



mains and depositions of shell-fish, and other
marine animals. The first who combated this
opinion was Palassou, in his celebrated essay on
the mineralogy of the Pyrenees, published in



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