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under the guidance of their teacher, Otto Schäfer
a) chrome alum octahedra embedded in alum cube (left) and alum octahedron,
b) seignette salt and potassium dihydrogen phosphate (front),
c) Mn-doped seignette salt (left), copper calcium acetate *6H2O and rocksalt*2glucose*H2O (right),
d) triglycine sulfate,
e) sodium chlorate (left) and sodium bromate,
f) nickel ammonium sulfate*6H2O (top) and lithium sodium chromate*6H2O,
g) + h) opals, diameters about 2 cm.
The coin has a diameter of 1.9 cm.
Crystals shown in fig.s a)-f) are permanently exhibited in the
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