felsite , auch: felstone

But the AltaRock project will, for the first time, drill deep into the felsite.

Phenocrysts are commonly found in materials such as felsite and andesite.

Felsite from Karnataka is being extensively used as a dimensional stone as well.

This is the time the church got its current form of a pink felsite basilica with three naves, the two side naves being narrow.

"Shetland knives" are stone tools that date from this period made from felsite from Northmavine.

The quarry at Balmullo extracts orange-pink felsite (red pathway chippings), and lies to the west of the village.

These cooled to form very hard granophyre and felsite rocks - in fact two 'rink dykes' or the "outer" and "inner" rings.

The two regional dykes (a leucograbbro and a felsite) from the Kerala region of southwestern India, which were also dated earlier, indicate the age as 85 Ma.

The conglomerates consist of grey feldspathic sand and well-rounded pebbles and cobbles of quartzite, granite, felsite, and quartz monzonite.

The walls were of a sort of gray felsite, and here and there one appeared to be better built than the others, as though built by different hands, by different thinking.

Above the magma is a layer of granite-like rock called felsite, which transmits heat to a thick layer of sandstone-like material called graywacke, riddled with fractures and filled with steam.

Cryptocrystalline tool stones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite, which are igneous flowstones; and obsidian, a form of natural glass created by igneous processes.

In some cases, felsic volcanic rocks may contain phenocrysts of mafic minerals, usually hornblende, pyroxene or a feldspar mineral, and may need to be named after their phenocryst mineral, such as 'hornblende-bearing felsite'.

The Sax Dome contains an upper portion of cream coloured, aphanitic to fine quartz porphyry felsite with abnormal green glass filled fractures, and a lower unit of microsyenite with red and green glassy zenocrysts.

Geologically, the two Dirrington Laws comprise Carboniferous volcanic felsite (riebeckite), and may be the remains of a laccolith, a type of volcanic intrusion into the surrounding sedimentary rocks of the Old Red Sandstone.

The mass of the rock consists of a fine-grained matrix of felsic materials, particularly quartz, sodium and potassium feldspar, and may be termed a quartz felsite or quartz porphyry if the quartz phenocrysts are present.

Cryptocrystalline or amorphous stone such as chert, flint, obsidian, and chalcedony, as well as other fine-grained stone material, such as rhyolite, felsite, and quartzite, were used as a source material for producing stone tools.

The existence of felsite and andesite at Haddington Island suggests it might have formed 3.7 million years ago as the Juan de Fuca and Explorer Plate to its west have been subducting under the North American Plate at the Cascadia subduction zone.

They can contain a very great variety of minerals, the principal ones being quartz, orthoclase and plagioclase feldspars, calcite, iron oxides and graphitic, carbonaceous matters, together with (in the coarser kinds) fragments of such rocks as felsite, chert, slate, gneiss, various schists, and quartzite.