Glass is not just that window or mirror we have in our houses, it's also an art and a craft that is hard to master, Egyptians are known to have mastered the art of glass for thousands of years. Glas is made from the pure white sand that comes from the deserts of Egypt, so it was easy for Egyptians to get quickly inspired by the Idea of mastering the art of glass. Either by hand made moulded bottles or by filling a glass bottle with coloured sand. Which is a craft that is admired by all of Egypt's visitors alike.
The art of glass is one of the oldest crafts known to the Egyptians, even nowadays you can find street sellers selling their cheap bottles that they made at home, while elegant and beautifully crafted bottles are sold at fancy bazzars and antique shops.
It is said that taking a bottle full of sand home with you from Egypt is just like taking a peice of Egypt home with you, with all the elegance of history, and greatness of the Pharaohs, so if you do visit Egypt some day be sure to take a nice bottle full of sand home with you.