Silica, however, suggests itself as a suitable substance for such a test, both the crystalline forms and the under-cooled glass being readily obtained in a form suitable for mechanical tests.
Chalcogenides are compounds formed primarily from chalcogen elements such as sulphur, selenium or tellurium, and are very different from silica glass. Chalcogenides come in a variety of colours ...
The earliest makers pressed glass into molds. Around 1500 BCE, finer vessels were being made in Egypt. The best glass manufacturers and exporters of this time were the Phoenicians who had a great ...