EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing. To request an improvement, please leave a comment on the page.OL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing. To request an improvement, please leave a comment on the page.
Glass is made by melting sand,soda ash,lime,some recycled glass in a furnance at 1900 degree celsius in a liquid state it is drawn on molten lead to make the glass surface flaâ¦t and allowed to cool for 36 hours before packing.(the green colour in th glass appears due the iron content in it)
Obsidian, natural glass of volcanic origin that is formed by the rapid cooling of viscous lava. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass. Though obsidian is typically jet-black in colour, the presence of hematite (iron oxide) produces red and brown varieties, and the inclusion of tiny gas bubbles may create a golden sheen.