They are four important iron ores, magnetite, haematite, limonite and siderite, and one of less but still considerable importance, pyriteor pyrites.
Pyrite may be prepared artificially by gently heating ferrous sulphide with sulphur, or as brassy octahedra and cubes by slowly heating an intimate mixture of ferric oxide, sulphur and sal-ammoniac.
It occurs in nature as the mineral melanterite, either crystalline or fibrous, but usually massive; it appears to have been formed by the oxidation of pyrite or marcasite.
But to the depth of about fifty feet from the surface the pyrite of the vein has been dissolved, leaving a rusty, cellular quartz with grains of the insoluble gold scattered through it.
Pyrite is a very hard mineral of a pale brass color, found in scattered crystals in many rocks, and is composed of iron and sulphur (iron sulphide).
The cubes of pyriteare not always valueless, they may contain gold in addition to the iron and sulphur.
The gold having been set free from the close embrace in which the iron pyrite held it previous to the latter's oxidation, it is now readily caught by quicksilver.
Since the shortage of shipping shut off the foreign supply we are using more of our own pyrite and also our deposits of native sulfur along the Gulf coast.
At the close of the war supplies of pyritehad been accumulated to such an extent that, with the prospect of reopening of Spanish importation, pyrite production in the United States practically ceased.
Marcasite and pyrrhotite, other iron sulphide minerals, are frequently found with pyrite and are used for the same purposes.
The replacement of pyrite by sulphur in the manufacture of sulphuric acid has continued since the war, and in the future is likely to continue to play an important part.
Pyrite is also used in Europe for the manufacture of paper from wood-pulp, but in the United States native sulphur has thus far been exclusively used for this purpose.
The residue from the roasting of pyrite is a high-grade iron ore material frequently very low in phosphorus, which is desirable in making up mixtures for iron blast furnaces.
Usually the veins consist almost entirely of graphite, but sometimes other minerals occur in important amounts, especially pyrite and quartz.
Copper is known to be taken into solution as copper sulphate at the surface, and to be redeposited as chalcocite where these sulphate solutions come in contact with chalcopyrite or pyrite below.
Not only has the process been duplicated in the laboratory, but the common coating of chalcocite around grains of pyrite and chalcopyrite below the water level indicates that this process has been really effective.
In the Mississippi valley it is extracted as a by-product from the lead and zinc ores, and in the Cordilleran region large quantities of by-product pyrite could easily be produced if there were a local demand.
It is usually closely associated with iron pyrite in a matrix or gangue of quartz.
So far as there has been any noticeable effect on the gold content of the ores, it has been due to the leaching out of other constituents, principally pyrite and other sulphides, leaving the gold present in slightly larger proportions.
Where pyriteis present in abundance it easily weathers out, leaving iron-stained pits and releasing sulphuric acid which decomposes the rock.
A few small crystals of pyrite were then placed in the bottle of solution, and the gold began immediately to precipitate on them.
It was noticeable, however, that the pyrite crystals which were free from zinc, galena, or other extraneous matter received no gold precipitate.
Hence sable coal his massy couch extends, And stars of gold the sparkling pyrite blends.
Defn: A sulphide of iron resembling pyrite or common iron pyrites in composition, but differing in form; white iron pyrites.
It is found as a mineral, but is usually obtained as a by-product in burning pyrite in the sulphuric-acid industry.
Owing to the affinity of each component element for oxygen, pyrite often changes to vitriol, or else forms the oxide of iron, limonite, described below.
Pyrite consists of iron and sulphur; magnetite, hematite, and limonite are oxides of iron.
The stone known as lapis lazuli as it occurs in nature is not a single mineral but a mixture of several, among which are calcite, pyrite and pyroxene.
Grains of pyrite are also usually scattered through the stone giving the "starry" effect referred to by Pliny.
As an accessory rock-constituent, pyrite occurs usually in isolated cubes or pyritohedrons.
The most characteristic accessory constituents of norite, besides those already mentioned, are magnetite and chrysolite; though garnet, serpentine, and pyrite often occur.
Pyrite (sulphide of iron) is also a source of sulphur compounds.
Even when only a small proportion of mundic, pyrite or marcasite is present, it is highly objectionable for several reasons.
No, I do not think there is any of any consequence of iron pyrite in the Newcastle mines.
And yet it may be possible that there may be sulphur in the form of pyrite present in sufficient quantity to do its work.
Wherever flint and pyrite are to be had these are used for striking fire.
Here is also another winter resort of the tribe, from which the island Tukia, north of Lake Avatutiaq, is visited in summer, to collect pyrite or native iron (p.
The progress of science has, however, modified the state of things since then, as sulphur can now be obtained from pyrite or pyrite of iron.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "pyrite" in a variety of sentences. We hope that you will now be able to make sentences using this word.
