|
A fahlband is a stratum in crystalline rock, containing metallic sulphides.
 Research Fahlband
Fahlerz or gray copper ore, is of a steel-gray or iron-black colour mineral that occurs crystallized in the form of the tetrahedron and also massive and disseminated. Its fracture is uneven or imperfectly conchoidal. It consists of from 30 to 40 per cent of copper with iron and sulphur;
but it also contains in very variable proportions zinc, lead, antimony, and silver.
Research Fahlerz
Fahlunite or Falunite, named after Fahlun (Falun) in Sweden, is a hydrated silica of alumina, resulting from the alteration of iolite. It is a mineral of a greenish colour, occurring in six-sided prisms.
Research Fahlunite
The faluns is a series of strata, of the Middle Tertiary period, of France, abounding in shells, and used by Sir Charles Lyell as the type of his Miocene subdivision.
Research Faluns
In geology, a famp is an indurated wavy calcareous shale found among limestone rocks.
Research Famp
Farcilite was an old mineralogical term for a conglomerate.
Research Farcilite
Fassaite, named after the Fassa valley in the Tyrol, is a variety of pyroxene.
Research Fassaite
Faujasite, named after the French geologist Faujas de Saint-Fond is a silicate occurring in square octahedrons together with black augite in the mandelstein of the Kaiserstuhl in Baden.
Research Faujasite
In geology, a fault is a dislocation caused by a slipping of rock masses along a plane of facture. The term also describes the dislocated structure resulting from such slipping. The surface along which the dislocated masses have moved is called the fault plane. When this plane is vertical, the fault is a vertical fault; when its inclination is such that the present relative position of the two masses could have been produced by the sliding down, along the fault plane, of the mass on its upper side, the fault is a normal, or gravity, fault. When the fault plane is so inclined that the mass on its upper side has moved up relatively, the fault is then called a reverse (or reversed), thrust, or over thrust, fault. If no vertical displacement has resulted, the fault is then called a horizontal fault. The linear extent of the dislocation measured on the fault plane and in the direction of movement is the displacement; the vertical displacement is the throw; the horizontal displacement is the heave. The direction of the line of intersection of the
fault plane with a horizontal plane is the trend of the fault. A fault is a strike fault when its trend coincides approximately with the strike of associated strata (i.e., the line of intersection of the plane of the strata with a horizontal plane) ; it is a dip fault when its trend is at right angles to the strike; an oblique fault when its trend is oblique to the strike. Oblique faults and dip faults are sometimes called cross faults. A series of closely associated parallel faults are sometimes called step
faults and sometimes distributive faults.
Research Fault
Favosites (favosite) is a genus of fossil zoophyta resembling a honeycomb in appearance and common in the Silurian strata of Norway and Wales
Research Favosites
Fayalite, named after the island of Fayal, is a black, greenish, or brownish mineral of the chrysolite group. It is a silicate of iron.
Research Fayalite
Feather alum or halotrichite, is a hydrous sulphate of alumina, resulting from volcanic action, and from the decomposition of iron pyrites.
Research Feather Alum
Feather ore is a sulphide of antimony and lead, sometimes found in capillary forms and like a cobweb, but also massive. It is a variety of Jamesonite.
Research Feather Ore
Feitsui is the Chinese name for a highly prized variety of pale green jade.
Research Feitsui
Feldspar or felspar is a name given to a group of minerals, closely related in crystalline form, and all silicates of alumina with either potash, soda, lime, or, in one case, baryta. They occur in crystals and crystalline masses, vitreous in lustre, and breaking rather easily in two directions at right angles to each other, or nearly so. The colours are usually white or nearly white, flesh- red, bluish, or greenish. The group includes the monoclinic (orthoclastic) species orthoclase or common potash feldspar, and the rare hyalophane or baryta feldspar; also the triclinic species (called in general plagioclase) microcline, like orthoclase a potash feldspar; anorthite or lime feldspar; albite or soda feldspar; also intermediate between the last two species, labradorite, andesine, oligoclase, containing both lime and soda in varying amounts. The feldspars are essential constituents of nearly all crystalline rocks, as granite, gneiss, mica, slate, most kinds of basalt and trachyte, etc. The decomposition of feldspar has yielded a large part of
the clay of the soil, also the mineral kaolin, an essential material in the making of fine pottery. Common feldspar is itself largely used for the same purpose.
Research Feldspar
Felsite or felstone is a hard, compact, volcanic, fine grained rock, flint-like in fracture, consisting essentially of orthoclase feldspar with occasional grains of quartz occurring in the older geological formations.
Research Felsite
Fengite is a kind of marble or alabaster, formerly sometimes used for windows on account of its transparency.
Research Fengite
Ferberite is the chief ore of tungsten. It is a rare mineral found usually in pegmatite dikes and high- temperature quartz veins associated with granite. It has the formulae FeWO4 - MnWO4 and a relative hardness of 6.
Research Ferberite
Fergusonite, named after Robert Ferguson, is a mineral of a brownish black colour, essentially a tantalo- niobate of yttrium, erbium, and cerium.
Research Fergusonite
Ferruginous refers to containing iron.
Research Ferruginous
Fichtelite is a white crystallized mineral resin from the Fichtelgebirge, Bavaria.
Research Fichtelite
Fiorite, so called from Fiora, in Ischia, is a variety of opal having a pearly lustre, occurring in the cavities of volcanic tufa, in smooth and shining globular and botryoidal masses.
Research Fiorite
Fire-clay is a compact kind of clay, consisting chiefly of silica and alumina, capable of sustaining intense heat, and used in making fire-bricks (for furnaces), gas-retorts, crucibles, etc. Fire-clay is found in various regions, but the most highly esteemed is that of Stourbridge, which resists very high temperatures. Fire-clay generally belongs to the coal formation, forming a stratum immediately below each seam of coal.
Research Fire-Clay
A fiveling is a compound or twin crystal consisting of five individuals.
Research Fiveling
In geology, a flag is a hard, evenly stratified sandstone, which splits into layers suitable for flagstones.
Research Flag
Flint is a massive compact variety of quartz comprised of fine grained silica. It is usually grey to brown or nearly black in colour and breaks with a conchoidal fracture and sharp edge. It is amorphous, and usually occurs in nodules or rounded lumps. Its surface is generally uneven, and covered with a whitish rind or crust, the result of weathering or of the action of water percolating through the rocks. It is very hard, and strikes fire with steel, and is an ingredient in glass and in all fine pottery ware. Its true native place is the upper bed of the chalk formation, in which it is formed as a series of concretions, the silica in sponges and in other marine animals which lived on the sea floor while the chalk was being deposited being attracted into nodules.
Research Flint
Floating quartz or floatstone is a porous variety of quartz of a spongy texture, whitish-grey in colour, so light as to float in water. It frequently contains a nucleus of common flint.
Research Floating Quartz
In geology, flocculation is the process by which small particles of fine soils and sediments aggregate into larger lumps.
Research Flocculation
Flos-ferris is a variety of aragonite, occurring in delicate white coralloidal forms commonly in beds of iron ore.
Research Flos-Ferri
Flourite is a mineral usually found occurring in isometric cubic crystals or in massive formations. It is comprised of calcium fluoride with small amounts of yttrium and cerium. Flourite has a relative hardness of four and a low melting point. It is used as a flux in the smelting of metallic ores and as a semi-precious gem stone in jewellery.
Research Flourite
Flow banding refers to a structure sometimes found in volcanic rocks where alternating layers of rock have different mineral compositions.
Research Flow banding
Fluocerine is a fluoride of cerium, occurring near Fahlun in Sweden.
Research Fluocerine
Fluorapatite is a common mineral consisting of a mixed phosphate and fluoride of calcium. It is a source of phosphorus and was formerly used to make phosphate fertiliser.
Research Fluorapatite
Fluorite (calcium fluoride) or fluorspar or Derbyshire-Spar is a mineral occurring in many different colours, found in veins where it's the main mineral or with metallic ores, especially lead and silver. It generally occurs massive, but crystallizes in simple forms of the monometric system: the cube, octahedron, dodecahedron, etc, and in combinations of the cube and octahedron. It is common in dolomites and limestone and is associated with many different minerals. From the general prevalence of a blue tint in the Derbyshire specimens it is there known as Blue-John. It is often beautifully banded, especially when in nodules, which are much prized for the manufacture of vases, and it is made into a great variety of articles, chiefly ornamental. It is used chiefly as a flux in the making of steel, and also for enamelling, and in the preparation of hydrofluoric acid. It is a fluoride of calcium with the formulae CaF2 and a relative hardness of 4.
Research Fluorite
In geology, the term fluvio-marine describes deposits formed by the joint action of a river and the sea, such as deposits at the mouths of rivers for example.
Research Fluvio-Marine
The Flysch is a name given to the series of sandstones and schists overlying the true nummulitic formation in the Alps, and included in the Eocene Tertiary.
Research Flysch
In geology, the term foliation refers to the property, possessed by some crystalline rocks, of dividing into plates or slabs, which is due to the cleavage structure of one of the constituents, as mica or hornblende. It may sometimes include slatey structure or cleavage, though the latter is usually independent of any mineral constituent, and transverse to the bedding, it having been produced by pressure.
Research Foliation
A foralite is a tube-like marking, occurring in sandstone and other strata.
Research Foralite
Forest Marble is an argillaceous laminated shelly limestone, alternating with clays and calcareous sandstones, and forming one of the upper portions of the Lower Oolite. It is so called from Whichwood Forest, in Oxfordshire, where the finer bands are quarried as marble.
Research Forest Marble
In geology, a formation is any series of rocks referred to a common origin or period, whether they consist of the same or different materials. Geological strata are divided into certain groups of one era of deposition, sometimes of very dissimilar mineralogical character, but inclosing the same fossil species; such as, the Carboniferous, Oolitic, Cretaceous, Silurian, Laurentian, etc.
Research Formation
Fowlerite, named after Dr. Samuel Fowler, is a variety of rhodonite, from Franklin Furnace, New Jersey, containing some zinc.
Research Fowlerite
In mineralogy, fracture is the manner in which a mineral breaks, and by which its texture is displayed; thus, an even fracture shows a level face or plane of some extent; uneven, when the surface is rough and broken; conchoidal, when one side is convex and the other concave, as in a molluscous shell; fibrous, when the separated edges have the appearance of torn filaments; hackly, when there are many fine sharp points or inequalities.
Research Fracture
Francolite is a variety of apatite from Wheal Franco in Devonshire.
Research Francolite
Franklinite is a mineral found in Franklin, New Jersey, and used as an ore of zinc and manganese. With minor exceptions, the mineral is confined to Franklin, New Jersey. It has the formulae (Zn,Mn,Fe)(Fe,Mn)2O4 and a relative hardness of 7. Franklinite exhibits increased magnetism when it is heated.
Research Franklinite
Freibergite is a variety of terahedrite containing between 28 and 36 percent silver.
Research Freibergite
French chalk is a variety of granular talc. It is used for drawing lines on cloth and is used by athletes and gymnasts to put on their hands to stop them slipping. In painting and decorating, French chalk is sometimes incorporated into paint as an extender to help keep the pigments in suspension.
Research French Chalk
Friable refers to crumbles or is pulverized easily.
Research Friable
In geology, the term fucoidal refers to rocks containing impressions of fossil fucoids or seaweeds such as fucoidal sandstone for example.
Research Fucoidal
Fulgurite is a term applied to rocks whose surface has been melted by the action of lightning, and on which the fused material has re-solidified as a kind of thin coat or varnish. More strictly, the term is applied to a vitrified tube of sand formed by the intense heat of lightning penetrating the sand, and fusing a portion of the materials through which it passes.
Research Fulgurite
Fuller's earth is a kind of clay or marl, compact but friable, unctuous to the touch, and of various colours, usually with a shade of green and highly absorbent properties, composed chemically of hydrous silicate of alumina. It is useful in scouring and cleansing cloth, as it imbibes the grease and oil used in preparing wool and derives its name from being used by fullers in the cleaning and felting of cloth. It consists of silica 50 per cent, alumina 20, water 24, and small quantities of magnesia, lime, and peroxide of iron. There are very extensive beds of this earth in several counties in England.
Research Fuller's Earth
|
Abbreviations
Rocks & Minerals
