गडद ऍसिड ग्रॅनाइट ग्लास,

pitchstone's Usage Examples:

Thick viscous pitchstone lava of rhyodacitic composition flowed out, filling a river valley.

granodiorite, greenstone, labradorite, limestone, marble, melaphyre, pitchstone, pumice, pyrophyllite, quartz, quartzite, sandstone, schist, serpentinite.

a volcanic glass; however, unlike a glass, pitchstone has an irregular hackly fracture not a conchoidal fracture.

built on a foundation of massive rhyolite, massive pitchstone, and associated unmassive pitchstone agglomerate geologic formations adjacent to the Owyhee.

Òigh-sgeir is composed of hexagonal pitchstone columns.

Stone items were made from local and imported materials including flint, Arran pitchstone and chert, and included scrapers, arrowheads and cutting tools.

Constituents include porphyritic and non porphyritic rhyolite, obsidian, pitchstone, tuff, and agglomerate.

water worn pebbles of pitchstone, a highly silicious volcanic glass associated with tachylite on the Coliban River.

Flint and stone tools were found, as well as a piece of pitchstone thought to have come from the Isle of Arran.

They are often visible in specimens of obsidian, pitchstone and rhyolite as globules about the size of millet seed or rice grain,.

water worn pebbles of pitchstone, a highly silicious volcanic glass associated with tachylite on the Coliban.