Natural glass, like obsidian, is a dense volcanic glass and has been used by humans for thousands of years. For early humans, obsidian glass is a very rare and valuable product due to the way volcanic glass breaks and sharp edges are produced. This inherent quality of natural cut glass is used and often becomes sharp spearheads and knives.
If you don't know how to cut glass, one option is to buy a precut form from https://www.artglasssupplies.com/coe90-glass-precut-shapes molten glass.
Artificial glass base made of silica sand, plant ash and lime. In ancient times, glass pieces were valued as substitutes for precious stones or gems.
During the first century BC, glass melting and blowing became objects that can be developed. Glass pieces and objects gradually became more common after the discovery of blown glass. Objects such as vases, bottles, and cruets were mouth-blown and molded during the Roman Empire, usually for normal purposes and daily use.
Plain glass generally has a greenish hue. The green color is caused by a very small amount of iron impurities in the sand used to make glass.
A glass of red, blue and green becomes frequent. After artisans learned to mark and cut glass, they found that the refracted light from the clear glass was spectacular. Therefore, transparent glass became popular and the demand for colored glass plummeted.