History of glass
Glass remained a luxury material, and the disasters that overtook Late Bronze Age civilizations seem to have brought glass-making to a halt. It picked up again in its former sites, Syria and Cyprus, in the 9th century BC, when the techniques for making colorless glass were discovered. The first glassmaking "manual" dates back to ca. 650 BC. Instructions on how to make glass are contained in cuneiform tablets discovered in the library of the Assyrian king Ashurbanipal. In Egypt glass-making did not revive until it was reintroduced in Ptolemaic Alexandria. Core-formed vessels and beads were still widely produced, but other techniques came to the fore with experimentation and technological advancements. During the Hellenistic period many new techniques of glass production were introduced and glass began to be used to make larger pieces, notably table wares. Techniques developed during this period include 'slumping' viscous (but not fully molten) glass over a mould in order to form a dish and 'millefiori' (meaning 'thousand flowers') technique, where canes of multicolored glass were sliced and the slices arranged together and fused in a mould to create a mosaic-like effect. It was also during this period that colorless or decolored glass began to be prized and methods for achieving this effect were investigated more fully.
Sea glass
For instance, in Jamaica there are influxes of Spanish, African, English, American, East Indian, Chinese, and Jews (who incidentally arrived about the same time Christopher Columbus' son arrived to settle the island in 1510 and many later shipped with the Caribbean pirate crews) and other Europeans scattered throughout the historical record. The majority of black glass found on the island of Jamaica is English glass produced from the later 1600s until the 1800s in England. Sea glass arrived in Jamaica with the old world supply chain first established in the 15th century. The Spanish considered Santiago (Jamaica) a backwater to Cuba, and this allowed the English to relieve them of it in 1655 without much resistance. The first man-made glass most likely arrived with Christopher Columbus on his 2nd voyage when he claimed the island for Spain in 1494. He is reported to have landed at Dry Harbor, Discovery Bay on the north coast. Whether any of the glass on board became sea glass is part of the romance and wonder of beachcombing.