Classifica tion. 3. Rustling, as in passing the finger over mountain cork and farinaceous zeolite. 2. Particular generic characters of friable minerals. The characters included under this title are the external form, the lustre, the appearance of the particles, the stain and the friability. I. The external form, which is either massive, as in porcelain earth; interspersed, as in black silver ore; as a thick or thin crust, as in black copper ore; spumiform, as in red and brown scaly iron ores; dendritic, as gray ore of manganese; or reniform, as pure clay and earthy talc. II. The lustre, which is determined as in solid minerals; but here it is distinguished, 1. With regard to intensity, as A.Glimmering, as in earthy talc and scaly iron ore; and, 2. With regard to the kind, as it is common or metallic. III. The appearance of the particles, which is either, IV. The stain is distinguished in friable minerals as being either 1. Strong, as in scaly iron ore. 2. Weak, as in earthy lead ores. V. The friability, with regard to which friable minerals are either, 1. Pulverulent, as earthy lead ores, and blue martial earth. 2. Loosely coherent, as scaly iron ore and clays. 3. Particular generic characters of fluid minerals. These characters relate to the external form, the lustre, the transparency, the fluidity, and, the wetting, of the fingers. I. The external-form, which is either, 1. In globules; and, 2. Liquiform; both which characters belong to native mercury. II. The lustre, which is determined as formerly explained, and is either, 1. Common; or, 2. Metallic, as in native mercury. III. The transparency, of which three degrees are distinguished in fluid minerals: 1. Transparent, as in naphtha; 2. Turbid, as in petroleum; 3. Opake, as in native mercury. IV. The fluidity, which is characterised by being, 1. Perfectly fluid, as mercury, and, 2. Cohesive, as in mineral tar. V. The wetting of the fingers. 1.Some fluid minerals wet the fingers, as mineral tar; and, 2. Some do not, as native mercury. Remaining Common Generic External Characters. The remaining common generic characters are the unctuosity; the coldness; the weight; the smell; and the taste. 3. Slightly cold, as amber, pitcoaf, and chalk. By this character cut and polished stones may be distinguished, where some of the other characters are lost; and by it also natural gems may be distinguished from those which are artificial. V. The weight. This character is most accurately discovered by taking the specific gravity of a mineral by means of a hydrostatic balance. See HYDRODYNAMICS. But when this cannot be had recourse to, a mineral is examined by lifting it in the hand, and comparing its weight, thus estimated by the feeling, with its valume, by which means an approximation may be made to its specific gravity. Five degrees of this mode of estimating the weight of minerals have been assumed. 1. Supernatant, such minerals as swim in water, as naphtha, mountain cork. 2. Light, such minerals as have a specific gravity between 1.000.and 2.000, (taking water at 1.000) as amber, mineral pitch, and pitcoal. 3. Rather heavy, are such minerals as have a specific gravity between 2.000 and 4.000, which is the case with most kinds of stones, as amianthus, rock crystal, mica, fluor spar, diamond. 4. Heavy, when the specific gravity is from 4.000 to 6.000, as in most metallic ores, such as gray copper ore, red hæmatites.. white lead ore, and in some others as heavy_spar. 5. Extremely heavy, when the specific gravity exceeds 6.000, which includes the native metals, as native gold, native copper, and native silver, and some others, as galena, tinstone crystals, sulphurated bismuth, and vitreous silver ore. VI. The smell is characteristic of only a small number of minerals. It is observed either, A. Urinous, as in swinestone after rubbing. C. Garlic, as in arsenical pyrites and white cobalt ore. D. Empyreumatic, as in quartz and pitcoal. VII. The taste, which is characteristic of one class of minerals, only, viz, the salts; and it is either, 1. Sweetish saline, as rock salt. 2. Sweetish astringent, as native alum. 7. Urinous, as native sal ammoniac. Beside the characters which we have now illustrated, some others are occasionally and successfully employed in the description of minerals. These have been brought under Classifica tion Classifica, under the denomination of physical, chemical, and emtion pirical characters. 1. Physical. The most common of the physical characters is the property which some minerals possess of exhibiting signs of electricity and magnetism. Some minerals become electric by being heated, and others by friction; and the electricity thus excited is in some vitreous or positive, and in others resinous or negative. Some minerals, too, and particularly some varieties of iron ore, are distinguished by being attracted by the magnet. Such are magnetic pyrites, and magnetic iron sand. By filing a mineral so fine that the particles shall swim on water, and then applying a magnet, the slightest degree of magnetic effect may be observed. Among the physical properties of minerals also, may be reckoned the phosphorescence, which is produced by friction, as in some varieties of blende; or by exposure to heat, as fluor spar, and some calcareous spars. To these characters also belongs the peculiar property of Lemnian earth and some other boles, which being thrown into water split into pieces with a crackling noise; and the property of some opals and other stones, of acquiring a higher degree of transparency when they are immersed in water, hence called hydrophanes. 2. Chemical characters.-By some simple experiments, the nature of many mineral substances may be easily and quickly ascertained, and particularly by means of acids. Thus, the nitrous acid is employed to discover whether a mineral effervesces, from which character the nature of the mineral can be more certainly known than by any other. Ammonia, or the volatile alkali, dissolves copper, and assumes a blue colour. Acetic acid is successfully employed as a test of lead, which communicates to the acid a sweetish taste. By means of heat, and particularly by the use of the blowpipe, much knowledge may be obtained of the nature of minerals. Some are volatilized; in others the colour is changed; and while some are nearly fused at different temperatures, others burn with a flame of peculiar colours. 3. Empirical characters.-Among these characters, the most common is the peculiar efflorescence which takes place in some ores. In copper ores the efflores. cence is green or blue; in iron ores, brown, yellow, or red; in cobalt, peach blossom red; and in arsensic, white. Characters for the distinction of minerals may be obtained from the circumstance of certain minerals being found generally accompanying others; as native arsenic with orpiment; gray copper ore with copper pyrites, But it is obvious that this abridged mode of expressing these characters, by means of numbers, can only be advantageously employed by those who have made themselves quite familiar with the different numbers corresponding to the different shades of character, and who can thus recollect them with facility and precision. To others this method of description, by requiring constant reference to the explanation, may prove rather embarrassing, so that what is gained in brevity may be lost in perspicuity. We propose, therefore, still to retain the verbal mode of expression in preference to the numerical. TABLE OF MINERALS arranged in the order of their Genera and Species, each Genus being divided into Families or Groupes, the characters of which latter are derived from their external properties according to the method of Werner. c. RadiatedStilbite. Cubizite, Chabasie or Analcime. Cross-stone, Staurolite. Laumonite. Dipyre. Natrolite. Azurite. f. Ferruginous quartz, or iron flint. Hornstone. a. Splintery. b. Conchoidal. c. Ligniform. Flinty slate. a. Common. b. Lydian stone. Arctizite or Wernerite. Diaspore. Spodumene. Meionite. Sommite. IV. ÁRGILLACEOUS Gen. Native alumina. Common clay. a. Loam. b. Pipe clay. c. Potters clay. d. Variegated clay. Claystone. Clay Slate Family. Whet slate. Clay slate. Mica Family. e. Agate. f. Opal. Chrysoprase. Plasma. Cats eye. Lepidolite. Pitchstone Family. Mica. c. Labradore. d. Schistose. Basalt. Wacken. Phonolite or Clinkstone. Lava. Fluor. a. Earthy. b. Compact. c. Fluor spar. Family of Sulphates. a. Earthy. c. Foliated. d. Fibrous. Selenite. Anhydrite. Cube spar. VII. BARYTIC Genus. Family of Carbonates. Witherite. Family of Sulphates. d. Foliated. VIII. STRONTIAN Genus. Family of Carbonates. Strontites. Family of Sulphates. Celestine. a. Fibrous. b. Foliated. SECOND CLASS. I. Genus SULPHATES. Liver ore of mercury. a. Compact. b. Slaty. Cinnabar. a. Common. b. Fibrous. IV. SILVER Genus. Native silver. a. Common. b. Auriferous. Antimonial silver ore. Arsenical silver ore. Corneous silver ore. Sooty silver ore. Vitreous silver ore. Brittle vitreous silver ore. Red silver ore. a. Dark red. b. Bright red. White silver ore. Black silver ore. V. COPPER Genus. a. Compact. c. Capillary. Brick red copper ore. a. Earthy. b. Indurated. Emerald copper ore. Azure copper ore. a. Earthy. b. Indurated. Malachite. a. Fibrous. b. Compact. Green copper ore. a. Common. d. Compact. b'. Foliated. b. Micaceous iron ore. Red iron ore. a. Red iron froth. b. Compact. a. Brown iron froth. c. Brown hæmatites. a. Compact. b. Black hæmatites. Argillaceous iron stone. a. Red chalk. b. Columnar argillace ous iron stone. c. Granular. d. Common. e. Reniform. f. Pisiform. Bog iron stone. a. Morassy. Blue earthy iron stone. Green earthy iron stone. VII. LEAD Genus. Galena. a. Common. b. Compact. Blue lead ore. Brown lead ore. Black lead ore. White lead ore. Green lead ore. Red lead ore. Yellow lead ore. Native sulphate of lead. Earthy lead ore. a. Friable. b. Indurated. VIII. TIN Genus. Tin pyrites. Common tinstone. IX. BISMUTH Genus. Native bismuth. X. ZINC Genus. Blende. a. Yellow. b. Brown. c. Black. Calamiue. XI. ANTIMONY. Native antimony. Gray ore of antimony. T 2 a. Compact. b. Foliated. c. Radiated. d. Plumose. XII. COBALT Genus. b. Indurated. a. Earthy. b. Radiated. XIII. NICKEL Genus. Copper-coloured nickel. Nickel ochre. XIV.MANGANESE Genus. Gray ore of manganese, a. Radiated. Classification. One Species. DIAMOND. Id. Kirwin, I. 393. Le Diamant, Brochant, II. 153. Hauy, III. 287. Essential character.-Scratches all other minerals. External characters.-Its most common colours are grayish white and yellowish white; smoke gray and yellowish gray; clove brown; sometimes asparagus green, passing to pistachio green and apple green; sometimes a wine yellow and citron yellow, and also blue and rose red. When the diamond is cut, it presents a splendid and varied play of colours, which is one of its most striking characters. It is found sometimes in rounded grains, which are supposed to have been crystals with the edges worn; but it is most frequently met with crystallized. The primitive form is a regular octahedron, the integrant molecule a regular tetrahedron; but the form which it commonly assumes is the spheroidal, with 48 curvilineal faces, six of which correspond to the same face of the primitive octahedron. Besides this form there are various others, as the double three-sided pyramid, the dodecahedron, &c. All the modifications of the crystals of the diamond, Hauy observes, seem to be the effects of its tendency to crystallize in a regular figure of 48 plane faces, which, if it ever has existed, has not yet been discovered; and it is easy to conceive that this form would be produced by intermediate decrements on all the angles of the nucleus; but the deviations from this form seem to have been occasioned by its precipitate formation. The external lustre is from four to one; internal four. The fracture is straight foliated, with a fourfold cleavage, parallel to the faces of the octahedron; transparency four to three; hardness ten; brittle; specific gravity 3.518 to 3.600. Becomes positively electric Becomes positively electric by friction, even before it is polished. Chemical character.-When exposed to a sufficient temperature, it is entirely consumed. This has been fully ascertained by the experiments of modern chemists, from which it is concluded, that the diamond is entirely composed of pure carbone. See CHEMISTRY. Mr Boyle was the first, according to Henckel, who subjected the diamond to the action of heat, and in his experiments he found that it exhaled very copious and acrid vapours. This was about the year 1673; but in the year 1694 the experiment was repeated by the order of Cosmo III. grand duke of Tuscany. Diamonds were exposed to the heat of the powerful burning glass of Tschirnhausen, the action of which was even aided by means of another burning glass; and about the end of 30 seconds a diamond of 20 grains lost its transparency, separated into small pieces, and was at last entirely dissipated. The same experiment was repeated on other diamonds, always with the same result, and without exhibiting the least sign of fusion. Newton, in his treatise on Optics, has placed the diamond among combustibles, supposing that it is a coagulated unctuous substance. He had been led to this by observing its extraordinary refractive power, which in combustible bodies he found to be in a ratio considerably higher than their density. According to this general law he concluded, that the diamond as well as water contained an inflammable principle, both of which have since been verified. Newton's treatise was not published till 1704; but it appears that part of it was composed and read to the Royal Society in the year 1675, nearly 20 years before the Florentine experiments were made. ture. But nearly 70 years before this latter period, Boetius de Boodt, in his History of Stones, appears to have been perfectly satisfied, from an experiment which he describes, that the diamond was of an inflammable naThis document, which we presume will gratify the curiosity of many of our readers, is too singular to be omitted. "Mastix deinde calefieri parum, quemadmodum et adamas debet, idque, ut impositus ac supra positus mastici statim illi unione vera uniatur, ac vivos undique radios a se jaceat. Hanc unionem respuunt aliæ omnes gemmæ diaphana-cur vero legitimus adamas solus tincturam illam recipiat, aliæ gemmæ non, difficile est scire. Existimo mutuum illum et amicum amplexum propter similitudinem aliquam quam habent in materia et qualitatibus; hoc est, tota utriusque natura fieri, quod itaque mastix quæ igneæ naturæ est adamanti facile jungi possit, signum est; id propter materiæ similitudinem fier, ac adamantis materiam igneam, et sulphuream esse, atque ipsius humidum intrinsicum et primogenium cujus beneficio coagulatus est, plane fuisse oleosum et igneum, aliarum vero gemmarum aqueum.-Non mirum itaque si pinguis, oleosa, et ignea masticis substantia illi absque visus termino adpingi et applicari, aliis vero gemmis non possit." Boetius de Boodt, Gem. et Lapid. Hist. Hanoviæ, 1609. 4to. lib. ii. cap. I. Classifica For the sake of the English reader we shall translate this curious document. "If mastich and the diamond be exposed to heat, and brought into contact, they enter into perfect union, and emit a very lively flame, which does not take place in any other gem. But what is the reason that the diamond alone possesses this property? I am of opinion that this mutual combination arises from a certain resemblance which each of the substances possesses in its nature and properties: on this account, therefore, the mastich, which is of a combustible nature, may be united to the diamond from a similarity in their nature, which shows that the diamond is composed of combustible and sulphureous matter; and that the humid and original particles of its composition, by means of which it was coagulated, or assumed a solid form, have been decidedly of an oily and inflammable nature, while those of other gems have been of an aqueous nature. It is not, therefore, surprising that the fat, oily, and combustible substance of mastich may enter into intimate union with the diamond, but cannot be combined with other gems." tion. Localities, &c.-The diamond is found in various places of the East Indies, as in the provinces of Golconda and Visapour, in the peninsula of Hither India; and in the kingdoms of Pegu and Siam, in the peninsula of Farther India, and nearly, it is observed, in the same degree of latitude. In 1728 the diamond was discovered in Brasil, in the district of Serro-do-Frio, which is situated in the same southern latitude as the countries which produce the diamond on the north side of the equator. The native repository of the diamond, so far as is known, is a ferruginous soil, but whether it |