This is an extremely rare Roman dark blue heavy rough glass block with superb silver "Rainbow" iridescence patina, said to have been found in a Roman glass work place northern Israel! The pictures tells 101 tales
Glass is formed when sand (silica), soda (alkali), and lime are fused at high temperatures. The color of the glass can be altered by adjusting the atmosphere in the furnace and by adding specific metal oxides to the glass "batch" (such as cobalt for dark blue, tin for opaque white, antimony and manganese for colorless glass).
This was its origin: in a part of Syria which is called Phoenicia, there is a swamp close to Judaea, around the base of Mt. Carmel, from which the Bellus River arises . . . whose sands are purified from contamination by the torrent's flow. The story is that here a ship of natron [sodium carbonate] merchants had been shipwrecked; when they were scattered about on the shore preparing food and no stones were at hand for propping up their pots, they brought lumps of natron from the ship. The sand of the shore became mixed with the burning natron and translucent streams of a new liquid flowed forth: and this was the origin of glass.
(Isidore of Seville, Etymologies XVI.16. Translation by Charles Witke.)
Measurements: 17 cm - 10 cm - 7 cm
Condition: Intact as found
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