Note 1: Limonite is selected as a representative of iron ores in general.
Note 4: The quantity of stannous chloride required for the reduction of the iron in the limonite will be much larger than that added to the solution of iron wire, in which the iron was mainly already in the ferrous condition.
Note 3: A platinum crucible may be used for the roasting of the limonite and must be used for the fusion of the residue.
Determine the percentage of iron in a sample of limonite from the following data: Sample = 0.
Beds of limonite exist in the Linville range, in workable quantities, but it makes an inferior metal unless mixed with hematite or magnetite, which is found not far away.
There are many valuable beds of limonite or brown ore, extending in a zone from the northeastern foot-hills of the South mountains, into the Brushy mountains.
The weathering of limestones containing minor percentages of iron minerals originally deposited with the limestones may result in the residual concentration of bodies of limonite or "brown ores" associated with clays near the surface.
The iron sulphide commonly present in these ore bodies is oxidized to limonite at the surface, with the result that prospectors look for iron-stained rocks.
The gossans are formed by oxidation and leaching of other minerals from the deposits, leaving limonite or hematite in concentrated masses (see pp.
They are four important iron ores, magnetite, haematite, limonite and siderite, and one of less but still considerable importance, pyrite or pyrites.
When limonite is dehydrated and deoxidized in the presence of carbonic acid, it may give rise to chalybite.
On the other hand there are certain forms of ferric hydrate containing less water than limonite and approaching to haematite in their red colour and streak: such is the mineral which was called hydrohaematite by A.
Many deposits of limonite have been found, on being worked, to pass downwards into ferrous carbonate; and crystals of chalybite converted superficially into limonite are well known.
In iron-shot sands the limonitemay form hollow concretions, known in some cases as "boxes.
Deposits oflimonite in cavities may have a rounded surface or even a stalactitic form, and may present a brilliant lustre, of blackish colour, forming what is called in Germany Glaskopf (glass head).
Granular and concretionary limonite accumulates by organic action on the floor of certain lakes in Sweden, forming the curious "lake ore.
The various kinds of brown and yellow ochre are mixtures of limonite with clay and other impurities; whilst in umber much manganese oxide is present.
The large concentrations of limonite and clays may indicate mineral deposits exposed at the surface or buried up to several thousand feet below it (photograph courtesy of Melvin Podwysocki).
On this image, white and yellow colors indicate rocks rich in clay minerals and limonite in rocks of red and yellow hues.
Limonite and earthy hematites occur widely throughout the Appalachian region, in central New York, and westward to the Mississippi Valley.
Limonite occurs at the surface also, having been deposited in cavities and as a cement for loose fragments, particularly on the weathered outcrops of formations rich in iron.
On its surface are fragments of earthy limonite and siliceous rocks.
The surface is strewn with the fragments of flints and of a white chalcedonic quartz-rock; whilst the soil is friable and deep-red in colour, limonite in abundant fragments occurring on the ground.
It soon became apparent whilst examining these districts that one general condition prevailed whilst this extensive deposition of silica and the formation of the beds of limonite were in progress.
It is probable that some of the earthy limonite of the Kalikoso district contained originally iron carbonate and has been produced from concretions such as I have just described.
Such an explanation could not, I think, apply to the extensive area of the Kalikoso plains where the silicified corals are associated with limonite on the surface of a recently emerged area.
The larger fragments, 1 to 2 inches in size, represent the partial conversion into limonite of a basic volcanic rock with much glass in the groundmass which formed probably the surface of the basaltic flows of the plateaux.
In the Mbua plains, however, there are occasional small ponds and swamps, and there is no doubt that the limonite so bountifully represented on the dry districts is still in process of formation.
Except in the instance of the Kalikoso plains, the swamps and lakes have as a rule long since disappeared, their sites being alone indicated by the limonite on the surface.
The streak of limonite is yellow, thus distinguishing it from hematite.
Disseminated through beds of clay, limonite gives them the characteristic yellow color.
Pyrite consists of iron and sulphur; magnetite, hematite, and limonite are oxides of iron.
Such clays turn red when heated, since the water of the limonite is driven off, leaving hematite as a residue.
Bauxite is a limonite iron ore in which a part of the iron has been replaced by aluminum.
The powder and streak oflimonite are always yellow; it is an important ore.
In nature it is frequently altered to limonite with the separation of native sulphur.
The silicates derive their silica mainly from sand or infiltrated siliceous deposits; the alumina represents an admixture of clay; the iron came from limonite or hematite in the original state of the rock.
Thus it is seen that the iron-ores, as we pass from bog-limonite to magnetite, form a natural series similar to and parallel with that afforded by the coals as we pass from peat to graphite.
Magnetite is the richest in iron, and limonite the poorest.
Limonite and hematite are two great natural coloring agents, and almost all yellow, brown, and red colors in rocks and soils are due to their presence.
Thus limonite is never, hematite is usually, and magnetite is always, crystalline.
When first deposited, the ferric oxide is combined with water or hydrated, and is then known as limonite (specimen No.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "limonite" in a variety of sentences. We hope that you will now be able to make sentences using this word.
