Strabo Geography 16.2.25

[25] Then follows Ptolemaïs, a large city, formerly called Ace. ¹ It was the place of rendezvous for the Persians in their expeditions against Egypt. Between Ace and Tyre is a sandy beach, the sand of which is used in making glass. The sand, it is said, is not fused there, but carried to Sidon to undergo that process. Some say that the Sidonians have, in their own country, the vitrifiable sand; according to others, the sand of every place can be fused. I heard at Alexandria from the glass-workers, that there is in Egypt a kind of vitrifiable earth, without which expensive works in glass of various colours could not be executed, but in other countries other mixtures are required; and at Rome, it is reported, there have been many inventions both for producing various colours, and for facilitating the manufacture, as for example in glass wares, where a glass bowl may be purchased for a copper coin, ² and glass is ordinarily used for drinking.