It is a dense basic lava of a dark color, that breaks with a conchoidal or shell-like fracture, and shows a finely grained or hemi-crystalline texture in a glassy base.
They are usually compact and aphanitic, showing few if any plagioclase phenocrysts and having a semi-conchoidal fracture.
Whilst the glass retains its original bottle-green colour, it loses the clean sharpconchoidal edges and displays rough and uneven or granular borders.
It has a specific gravity of 2·36, is dark-brown, and has a conchoidal fracture.
Defn: A massive, somewhat impure variety of quartz, in color usually of a gray to brown or nearly black, breaking with a conchoidal fracture and sharp edge.
Defn: Any substance having a peculiar glassy appearance, and a conchoidal fracture, and usually produced by fusion.
A massive, somewhat impure variety of quartz, in color usually of a gray to brown or nearly black, breaking with a conchoidal fracture and sharp edge.
Any substance having a peculiar glassy appearance, and a conchoidal fracture, and usually produced by fusion.
Bulb of Percussion--a bulb resulting from a conchoidalfracture of stone.
Conchoidal (L)--shaped like half of a clam shell; refers to the characteristic fractures resulting from pressure and percussion flaking of flint.
It incloses angular and less friable masses of dark brown clay with a slaty and sometimesconchoidal fracture.
The serpentine is sometimes of an esquillous, sometimes of a conchoidal fracture: this was the first time I had found metalloid diallage within the tropics.
Some of the blackish varieties of this rock have a conchoidal fracture and resemble basalt; others have an irregular fracture.
Some of the small ones are made of flakes having the natural, conchoidal shape and worked on one side only.
A great portion of it, however, is compact, and has a flat conchoidal and slightly splintery fracture.
They are semi-diaphanous octahedrons, very brilliant on the surface, and of a conchoidal fracture.
The limestone of Barcelona has a dull, even, or conchoidal fracture, with very flat cavities.
These obsidians are, nevertheless, but little transparent on the edges; they are almost opaque, of a brownish black, and of an imperfect conchoidal fracture.
I had seen, while herborizing between the port of Orotava and the garden of La Paz, heaps of greyish calcareous stones, of an imperfect conchoidal fracture, and analogous to that of Mount Jura and the Apennines.
This mineral is tender, scarcely scratches calc-spar, and breaks easily with a waved conchoidal fracture.
This tool is not made of steel, because so hard a metal would render the strokes too harsh, or dry as the workmen say, and would shatter the nodules irregularly, instead of cutting them with a clean conchoidal fracture.
All volcanic rocks contain a greater or less quantity of titanic iron-ore, disseminated through them, which may be recognised by its brilliant metallic lustre, and its perfect conchoidal fracture.
It is of a red colour more or less deep, nearly transparent, and hard, with a brilliant conchoidal fracture.
It comes to us in large greenish-brown, semi-transparent lumps, having a conchoidal or splintery fracture, brittle and easy to pulverize.
It has a grayish black, or iron black colour, an imperfectly metallic lustre, conchoidal fracture, and a specific gravity of from 1.
Its colour is green; and its fracture is conchoidal with a resinous lustre, like most minerals which contain water.
A small oven upon the plan of a baker's, is best fitted for this purpose, which being heated to dull redness, and then extinguished, is ready to soften and afterwards anneal the conchoidal pieces.
It has a conchoidal fracture, and is without smell or taste.
Sea waves dashing pebbles about will sometimes produce a conchoidal fracture, but never a series of fractures in the methodical way in which a flint was worked by man.
I noticed some conchoidal hollows more than a foot in diameter.
It is generally slate-colored, with white specks, becoming a uniform white where exposed to the light and air, and it breaks with a conchoidal fracture, producing a ragged cutting edge.
Their surfaces often show minute crescentic or rounded cracks which are the edges of small conchoidal fractures produced by the impact of one pebble on another during storms or floods.
The purest flints have the most perfect conchoidal fracture, and prehistoric man is known to have quarried or mined certain bands of flint which were specially suitable for his purposes.
This material has a dull luster and a conchoidal fracture.
It has greater density than the lignites or subbituminous coals, is black, more brittle, and breaks with a cubical or conchoidal fracture.
The stone employed is almost always of a more or less silicious nature, and such as breaks with a conchoidal fracture.
When its color is dark brown, or gray, and it has a conchoidal fracture, it is flint.
When quartz occurs in white, tuberous masses, of a resinous lustre and conchoidal fracture, it is opal.
The fracture is described as conchoidalwhen it shows waving spherical surfaces like broken glass.
It is usually black and breaks with a perfect conchoidal fracture.
Remarkable freedom from cleavage so that the mineral breaks much like window glass—conchoidal fracture.
That material, as also some varieties of flint, breaks with a very clear, conchoidal fracture.
All the specimens discovered are glassy black, subtranslucent, and break with a clearconchoidal fracture.
It differs from jasper in breaking with a deeply conchoidal fracture and a sharp cutting edge.
Hornstone is more brittle than flint and has a splintery rather than a conchoidal fracture.
The paste is very fine grained, and breaks with a conchoidal fracture.
Usually the clay has been very fine grained, and when used without coarse tempering the vessels have an extremely even and often a conchoidal fracture.
Typical Mousterian 'points' from the type station of Le Moustier, made of a large flake of flint struck off from the nodule and retouched on only one side, leaving on the opposite side a smooth, conchoidal surface.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "conchoidal" in a variety of sentences. We hope that you will now be able to make sentences using this word.
