vitrifaction

Updated: May 9, 2025

The basement stage, assigned to Saturn, was blackened by means of a coating of bitumen spread over the face of the masonry; the second stage, assigned to Jupiter, obtained the appropriate orange color by means of a facing of burnt bricks of that hue; the third stage, that of Mars, was made blood-red by the use of half-burnt bricks formed of a bright red clay; the fourth stage, assigned to the Sun, appears to have been actually covered with thin plates of gold; the fifth, the stage of Venus, received a pale yellow tint from the employment of bricks of that hue; the sixth, the sphere of Mercury, was given an azure tint by vitrifaction, the whole stage having been subjected to an intense heat after it was erected, whereby the bricks composing it were converted into a mass of blue slag; the seventh stage, that of the Moon, was probably, like the fourth, coated with actual plates of metal.

George Rawlinson - The Seven Great Monarchies Of The Ancient Eastern World, Vol 4: Babylon : The History, Geography, And Antiquities Of Chaldaea, Assyria, Babylon, Media, Persia, Parthia, And Sassanian or New Persian Empire; With Maps and Illustrations.