Mill Tor consists of a peculiar granite; the feldspar is so pure that speculators have been induced to attempt to make soda-water bottles out of it, by fusing without the adjunct of other materials.
Large and beautiful crystals offeldspar characterise this rock.
At Vesuvius also, we perceive small crystals of vitreous feldspar only in the very ancient lavas of the Somma.
When the basis of the lavas of the Malpays changes from pitchstone to obsidian, its colour is paler, and is mixed with grey; in this case, the feldspar passes by imperceptible gradations from the common to the vitreous.
The feldspar approximates sometimes to vitreous feldspar when disseminated in very thin laminae in a mass of granular diabasis, decomposed, and emitting a strong argillaceous smell.
These balls are composed of lamellar feldspar and hornblende closely commingled.
They contain large nodules of reddish feldspar and but little quartz.
Montserrat, a solfatara; fine porphyritic lavas with large crystals of feldspar and hornblende near Galloway, according to Mr. Nugent.
The porphyries containing vitreous feldspar and hornblende, the phonolite, the greenstone, the amygdaloids, and the basalt, have forms almost as invariable as simple crystallized substances.
It contains also numerous veins and beds of hornblend rock and chlorite-schist, and of a peculiar-looking granite, of which the quartz is white as milk, and the feldspar red as blood.
A million sparks of light seemed to rise from the bed of feldspar over which the water leaped, and the peculiar quality of the rock gave to it the weird brilliancy which held us spellbound as we advanced with extreme caution.
We knew that the place was ugly and sinister, but feldspar and augite didn't give it that look.
It troubled me little at that moment whether feldspar and augite were the two largest components, and I knew that Holman and the two girls were not interested.
These ruin-like rocks command the plain; they are composed of a coarse-grained granite, nearly porphyritic, the yellowish white feldspar crystals of which are more than an inch and a half long.
The crystals of feldspar sometimes preserve externally their reddish-white colour, and rise above the black crust.
In the district of Glatz the fissures of the gabbro are filled with a steatite of a greenish white colour, and the rock which was long thought to belong to the grunsteins* is a close mixture of feldspar and diallage.
The nature of the phonolites, which are lithoid lavas with a feldspar basis, and the nature of the green slates intermixed with hornblende, oppose this opinion.
Among the phenocrysts feldspar is the most prominent.
The glassy rock has hypersthene as the predominant phenocryst, while feldspar is the more important in the compact and more crystalline andesite.
The upper portion of the granite shows the usual characteristics of weathering, namely, the conversion of feldspar into kaolin, the oxidation of iron, etc.
In the gneiss, concretions of granular feldspar and others of garnets with mica occur.
The lowest bed is of a pale purple colour, hard, fine-grained, and full of broken crystals of feldspar and scales of mica.
The prevailing rock is gneiss, often passing, by the disappearance of the quartz and mica, and by the feldspar losing its red colour, into a brilliantly grey primitive greenstone.
The prevalence of feldspar cleaving like albite, is common not only to the andesites, but (as I infer from the high authority of Professor G.
This stele bears a figure of the monarch; another one like it is cut upon a cylinder of green feldspar found by Layard close to the principal entrance to Sennacherib's palace (see Fig.
Quartz is glassy, mica is in scales, usually white or black, and feldspar is the opaque white or red mineral.
Potassium occurs only in combination, chiefly as silicates, in such minerals as feldspar and mica.
To glaze china, it is dipped into a powder of feldsparand SiO2 suspended in water and vinegar, and then fused.
Bracelets of white shells, a necklace of feldspar crystals and turquoises, and strings of yellow cotton threads around her ankles complete the costume.
Around his neck a string of crystals of feldspar was negligently thrown; and a fetich of white alabaster, representing rudely the form of a panther, depended from the necklace hanging upon his breast.
Her hair should hang loosely over the shoulders, the head encircled with a string of feldspar or pearl beads.
A kind of feldspar consisting of a laminated intertexture of albite and orthoclase, usually of different colors.
A term used somewhat loosely to designate a rock consisting of a fine-grained base (usually feldspathic) through which crystals, as of feldspar or quartz, are disseminated.
The process by which feldspar is changed into kaolin.
A kind of feldspar commonly showing a beautiful play of colors, and hence much used for ornamental purposes.
A mineral of the feldspar family, commonly occurring in small glassy crystals, also a constituent of some igneous rocks.
A mineral of the feldspar family, triclinic in crystallization, and in composition a silicate of alumina and soda.
The feldspar exhibited its splendent black crystals in fine relief in the massy quartz.
The completion of the gneiss in its entire separation from the granite, and the evolution of feldspar upon a large scale constitutes the clay-slate, and finally clay-stone and clay-porphyry.
The first structure, in which the character of feldspar as regards its laminated form and its more argillaceous nature obtains the preponderance, is Gneiss--Feldspar-granite.
If a schorl or feldspar were extended to the size of the whole earth, its integral parts, though undiscoverable before by the microscope, would then become visible.
Not only quartz is silicious earth, but feldspar and mica consist in a great measure of the same.
The fact cannot rest unobserved, that mica has only one laminar cleavage, feldspar two, quartz three, this being for the first time a perfect crystal, a double tetrahedron with one column.
But the bulk of the moraine is composed of porphyritic granite derived from Feldspar and Cathedral Valleys.
On examination, the rock consisted almost exclusively of red feldspar and quartz.
The feldspar and the mica, for example, as well as the schorl, are found variously coloured in different granites, and coloured in various proportions.
The term field spar, of which Feldspar is probably a corruption, was perhaps given the minerals of this group because of their widespread occurrence.
Labradorite has the typical cleavage of Feldspar and cleavage surfaces in the direction of easiest cleavage are usually marked by rows of parallel striae.
Another species of Feldsparused as moonstone is albite.
This is a soda Feldsparand is triclinic, but exhibits the color characteristic of moonstone.
The second species of Feldspar which may be mentioned as of use as an ornamental stone is labradorite.
Glass, however, lacks the cleavage of Feldspar and is somewhat heavier and softer.
The variety of Feldspar to which the sunstone most in use at the present time belongs is oligoclase, a soda-lime triclinic Feldspar.
Gems are occasionally cut from other forms of Feldspar than those here described, which are transparent and colorless and valued for their lustre.
Sunstone is the term by which those kinds of Feldspar are known which reflect a spangled yellow light.
Feldspar crystals can best be recognized by their prominent cleavage, which appears as numerous bright flat surfaces extending in any given crystal in the same direction.
Feldspar is the family name of several minerals closely related and indeed grading into each other, but distinguished by mineralogists by separate specific terms.
As ornamental stones only certain varieties of Feldspar are valued and their value depends on accidents of color or structure.
The Feldspar is usually well crystallized and crystals of several pounds weight may be found.
The Feldspar may, however, contain more or less iron and then take on a flesh color or become even darker.
The town stands on a basis of granite, the feldspar of which is for the most part of an opaque milk-white color, in a decomposing state; in some places it is found of a flesh-red color and crystallized.
Where the greenstone becomes porphyritic, the feldspar is a light green.
This granite is composed almost exclusively of reddish feldspar and quartz.
Mica and hornblende generally contain considerable oxide of iron, while feldspar usually yields only a trace or none.
The feldspar has been converted into slate, and the mica has parted with its iron.
When mica and hornblende are ground up, the result is blue or red clays, as the oxidation of the iron turns the clay red; while the clay made of feldspar is light yellow or white.
Mica and hornblende contain considerable oxide of iron, while feldspar has none.
Therefore clays which are derived from feldspar are light-colored or white, while those partially made up of decomposed mica or hornblende are dark, either bluish or red.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "feldspar" in a variety of sentences. We hope that you will now be able to make sentences using this word. Other words: alabaster; asphalt; mineral
