Page three of someone's report on... some precious stone.
...the grease. The screens are then taken away. Then the sparkling stones are separated. The rough stones are put in iron cars and escorted from the guard to the general office, they are cleaned and assorted as to size, color and purity. They are then sold to the local buyers at Antwerp and Amsterdam where they are cut in shapes.
Found in "Birds in Their Homes" by Addison Webb. Published by Garden City Books, 1947.
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