Man’s first efforts to make glass are unknown, but the Egyptians were the first to use glass in their culture and art. Amulets and solid glass beads were made in Mesopotamia circa 2500 BC, and the Egyptians began making glass 1000 years later. http://www.historyofglass.com/glass-invention/egyptian-glass/
The first glass vessels appeared during the reign of Tuthmosis I during the New Kingdom. In the Old and Middle Kingdoms, glass jewelry, amulets, and animal figures were created.
Extensive glass manufacturing began during the New Kingdom around 1550 BC, as it is believed that the craft of glass making was first introduced into Egypt by glass makers captured by Thutmose II, who reigned from 1479 BC to 1425 BC. During this period, attempts were made to use glass in more complicated projects, and the methods of core-forming and cold cutting were introduced. . http://www.historyofglass.com/glass-invention/egyptian-glass/
Core-forming is the technique of forming a vessel by winding or gathering molten glass around a core supported by a rod. After forming, the object is removed from the rod and annealed. After annealing, the core is removed by scraping. https://www.cmog.org/glass-dictionary/core-forming
When cold-working glass the material was treated similarly to stone. Blocks of it could be cut and ground to give them desired shape and drilled to create a hollow space. But glass being very brittle and easily shattered, this method was only rarely employed. http://www.reshafim.org.il/ad/egypt/glass/index.html Both methods were abandoned after the invention of the glass blowing technique during the Roman Era.
Decorations were added by pinching the hot glass, adding handles or other features to it like strands of differently colored glass which could then be pinched to change simple straight patterns into more intricate ones.
Coloring agents were naturally occurring impurities or metal oxides added on purpose. The much-coveted blue-tinted glass was made by adding cobalt. Yellow was the result of using iron and antimony, turquoise of copper or purple of manganese [3. Clear, almost colorless glass could be made by adding decoloring agents such as manganese oxide, as was done by the Romans. http://www.reshafim.org.il/ad/egypt/glass/index.html
In ancient Egypt, glass was regarded as an artificial semi-precious stone, and was given to favored subjects by royalty. The production of glass declined in Egypt after the 21st Dynasty (1096-945 BC). Although revived during the 26th Dynasty (664-525 BC), it continued on a much-reduced scale. . http://www.historyofglass.com/glass-invention/egyptian-glass/