Johan Rudolf Glauber (1604-1670) By Marieke Hendriksen The German apothecary and alchemist Johan Rudolf Glauber (1604-1670) spent much of his working life in Amsterdam. There, he used the facilities of a commercial glasshouse--"The Two Roses"--on the Rozengracht for some of his experiments.[1] By extracting the colours of metals by melting them into glass, Glauber hoped to come closer to the unveiling of the Philosopher's Stone.[2] Although he never achieved this, his experiments proved highl...