Lydite is the mineralogicalification of lydia stone (touchstone). A black, carbonaceous , radiolarian chert : a recrystallised radiolarite , with low porosity. Also used, confusingly, as a synonym of …

Radiolarites are biogenic, marine, finely layered sedimentary rocks. The layers reveal an interchange of clastic mica grains, radiolarian tests, carbonates and organic pigments. Clay …

A touchstone is a small tablet of dark stone such as slate or lydite, used for assaying precious metal alloys. It has a finely grained surface on which soft metals leave a visible trace. [1] The …

1985年1月1日 · Lydite-A velvet-black siliceous stone or flinty jasper, used on account of its hardness and black colour, for trying the purity of precious metals. The colour left on the stone …

touchstone, black siliceous stone used to ascertain the purity of gold and silver. Assaying by “touch” was one of the earliest methods employed to assess the quality of precious metals. …

2023年11月14日 · We studied the geochemistry of Paleoproterozoic siliceous rocks (lydites) from the North Onega synclinorium (Karelia). The study objects are represented by 16 lydite …

Siliceous slate, also known as lydite, is a rock that belongs to the group of sedimentary rocks and was formed in the sea. It is a dark gray to black variety of radiolarite formed during the …

2025年3月18日 · Synonym of lydite, which is a black variety of radiolarian chert. It was commonly used as a touchstone.

2007年1月11日 · Basanite is an eruptive rock (see also: http://gsa.confex.com/gsa/2003AM/finalprogram/abstract_65599.htm), while Lydite is …

2022年6月10日 · We found that at least four varieties of lydite (a type of basaltic rock, Lydite A, B, C, and D) and three varieties of red jasper (Jasper A, B, and C) were used in these sites. The …