PHOSPHORITE, APATITE. _nave Phosphate of lime, natural Bone-earth,. Under these various terms, nearly syno nymous, are comprehended a variety of mineral which is rather sparingly diffus ed, and has lately become of considerable value in an agricultural point of view, as a substitute for bone-dust and guano, and in a manufacturing point of view, as the crude material from which phosphorus may be readily obtained. _Apatite is a mineral which crystallizes in the regular six-sided prism usually terminated by a six-sided truncated pyramid ; it has usually a yellowish green tint, and is translucent. In hardness it ranks above fluorspar, and below feldspar. It is a compound of phosphate of lime with fluoride of calcium. It principally oc curs in primitive rocks, and is found in the tin mines of Cornwall, England, in those of Bohemia, Moravia, and Saxony, and from the rocks of St. Gothard. Apatite is found in granitiform rocks in New York, New England, and New Jer sey, in isolated crystalline masses. Its color is no distinguishing test, as it as sumes the tint of the neighboring rocks, being thins calculated to lead to decep tion as to its nature from whence it has derived its name (deceitful Gr.) Those of a bluish or green color may easily be mis taken for beryls. Some are colorless, violet, or lilac, and if not distinctly crys tallized may be mistaken for fluorspar. The specific gr. of the crystals of apatite is 3.1. They are soluble in nitric acid, and teonme phosphorescent when heated. Asparagus stone is of a green-yellow color, found in the Tyrol, where the crys tals are imbedded in talc. Moroxite is a name given to bluish-green crystals from Arndat, Norway. It is, however, un common to find it in large masses as well defined crystals. It is more common in the fibrous and amorphous condition. In the latter state it is known as phos phorite. This mineral is opaque, of a white or yellow-white tint, of a feathery structure, with numerous small cavities. This variety is massive, and at Lagrosso, in 1A1strernadura, Spain, forms entire hills : it is there used as it building stone. In Hungary phosphorite occurs of a loose earthy texture in thin beds. In this country, besides the localities of crystal line apatite, there are two locations where phosphate of lime occurs in ahnndanee ; one of these is near Crown Point, on Lake Champlain, where Dr. Emmons discovered it in situ. He has described it as being in beds of almost unlimited quantity, and of n great degree of purity, yielding as much as 93 per cent of phos phate of lime on analysis ; the gangue rock is serpentine, which communicates a green tint to the phosphorite of that locality. The other point where phos phorite is found, is in Morris County, New Jersey, near Pimple Hill, where it has been found as a vein, or dyke, run ning through a ferruginous feldspathic rock, which here tinges the phosphorite brownish red. This vein is semi-crystalline
in some spots, and of considerable purity. The extent of this vein has been traced in length for two miles, and it is stated to have a breadth of eight feet : five feet below the surface, it widens on quarry ing down. These are among the largest beds of phosphorite known, and are of incalculable value either for art, or for agriculture.
The analysis of the New Jersey bed of phosphorite, with the gangue or feld spathic rock hy which it was surrounded, made by the Editor, yielded the follow ing results in 100 parts.
No 1, was a mass of rhomboidal quartz with mica, and tinged with oxide of chrome.
No. 2, was the feldspathic gangue stone in the immediate vicinity.
No. 3, apatite from the vein. This sample, heated with sulphuric acid, gave off no hydrofluoric acid showing the absence of fluorspar, which, usually accompanies phosphate of lime. In its place, however, was substituted chloride of sodium, giving it some resemblance to the variety described by H. Rose as clor-apatite. The mineral found in New Jersey is very brittle, easily pulverized, and might be readilyground into powder, and made marketable as a substitute for bone-dust, of which it has precisely the mineral composition. Phosphorite, as a mineral, is found in primary rocks, and in contact with serpentine. Phosphate of lime has however been fonnd in England and Europe (continen tal), in other situations, as in beds of clay, of the secondary, and tertiary periods. Captain Ibbotson has found phosphate of lime in the chloritic marl of the Isle of Wight. This is geologically the upper green sand-bed immediately under the chalk-marl. In the lower part of the green sand-bed, ammonites and scaphites occur mixed with eoprolitie masses, rich in phosphate of lime ; the coprolites are now understood to be the fossil excretions of the Saurian tribes. Mr. Nesbitt has found in the chalk-marls phosphate of lime to the extent of two or three percent. Nodules (coprolitcs), from the pull, near Maidstone, England, have furnished twenty-eight per cent of phos phate of lime. The green sand, and upper secondary beds of this country, have not been examined sufficiently to determine whether it exists or not. Mr. Rogers, in his geological report of the State of New Jersey, looks upon the richness, as a manure, of the green sand to be duo to the potash present in it, of which substance, in some cases, he ob tained so much as seventeen per cent. Other analyses, by different chemists, have not supported this large amount of alkali, and it is probable that some of its fertility may be due to the presence of phosphate of lime.