It contains a very few pebbles of quartz, and occasionally layers of chalcedonic nodules, like those of chert in our Greensand.
They exhibit in the slides a patchy appearance, showing in some places finely granular crypto-crystalline silica and in others a coarser mosaic of chalcedonic quartz.
In another case the globular structure is less perfect, and the chalcedonic groundmass is penetrated by a multitude of fine cracks filled with iron oxide.
The casts of foraminifera are white and of chalcedonic silica.
Under the microscope it displays a fine radio-globular aggregate of chalcedonic quartz.
In the microscope slide the massive specimens appear to be entirely of chalcedonic silica, the outlines of the cells and of the septa being indicated by ferruginous material.
When in the Solomon Islands I was unable to find the source of the chalcedonic worked flints of such frequent occurrence in that region.
Under the microscope they exhibit a grey crypto-crystalline groundmass showing very finely granular crystalline silica with the cracks and small cavities filled with more brightly polarising chalcedonic quartz.
In the first place, it is a region of acid rocks, mostly altered tuffs, derived from quartz-porphyries, the alteration consisting in the deposition of quartz often of the chalcedonic type.
They were originally composed of finely pulverised basic vacuolar glass, which subsequently became palagonitised, and afterwards there was an extensive deposition of chalcedonic silica and of red iron oxide.
In a specimen of Porites by my side the crystallization of the silica has advanced beyond the chalcedonic stage and the coral is composed entirely of minute quartz-crystals, ·2 to ·4 mm.
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.
When examining the agates, the chalcedonic and jaspery rocks, some of the limestones, and even the bright red sandstones, I was forcibly struck with their resemblance to deposits formed in the neighbourhood of volcanic action.
In sinking wells in this district the chalcedonic strata seem to be the lowest.
The chalcedonic pebbles, when decorated with coloured markings, are called ‘agates.
Here are plenty of shingly beaches for you to choose from, and chalcedonic pebbles are common upon them all.
In other instances the pebble seems to have been originally a small fragment of chalcedonic quartz, such as composes some of the flakes and worked flints that are found in the soil which has been disturbed for cultivation.
These blades are from 7 to 9 1∕4 inches in length, and occasionally made of beautiful chalcedonic flint.
A beautiful adze formed of chalcedonic flint is shown in Fig.
Grindale, near Bridlington, is of transparent chalcedonic flint, beautifully and symmetrically worked over both faces.
It is formed of chalcedonic flint, and was found with others of ordinary types at Urquhart,[1742] Elgin.
It is formed of chalcedonic flint, and the sharp sides are partially smoothed by grinding.
A chalcedonic deposit in the form of concentric rings, on fossils and fragments of limestone in S.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "chalcedonic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
