The green colour, No. 2, is a much altered substance 
containing copper, and is probably the Chrysocolla of Theo¬ 
phrastus, Yitruvius, and Pliny. The mineral which we now 
term Chrysocolla, is a hydrated silicate of copper, whilst that of 
the ancients there is every reason to believe was the carbonate 
(Malachite). This will be seen from Pliny’s description, 
bearing in mind that copper is often found mineralised with 
gold, silver, and lead. “ Chrysocolla is a liquid wdiich is 
formed in the shafts flowing through veins of gold, a kind of 
slime which becomes indurated by the cold of winter until it 
has attained the hardness even of pumice. The most esteemed 
kind is found in copper mines. He then describes how an 
artiflcial Chrysocolla may be manufactured by allowing water 
to percolate through a vein of the metal, and allowing the 
former to evaporate.” 
Of the two reds which were examined, one was a dull red 
ochre, its colour being derived from ferric oxide. Several red 
earths used in painting are described by Theophrastus and 
Pliny as the Sinnian earth, the Armenian earth (Bole) and 
African ochre which had its red colour produced by calcination. 
The other red was a compound of lead and probably minium. 
The red lead oxide was known to the Grreeks under the name 
sandarake.” 
In parts of Pliny’s descriptions there is some confusion 
between minium and cinnabar. He says that sandarach w^as 
a product of an island in the Eed Sea, then he tells us ‘‘ that 
there is a sprmous kind prepared by calcining cerusse in the 
furnace,” and that this was discovered accidentally by means 
of a Are at the Piroeus at Athens. Some cerusse i.e. wfliite lead 
which had been exposed to the Are was found converted into 
minium, and afterwards the process was imitated artificially. He 
likewise describes another colour Sandyx, and which Beckman, 
from a passage in Yirgil, considers it to be our madder, Pliny 
also remarks that Yirgil has taken Sandyx to be a plant. But 
the naturalist’s description shows that this could not be true, 
for according to him it is prepared by calcining equal propor¬ 
tions of rubrica and sandarach, and the only effect of this 
operation would be to alter the tint of the pigment, and to give 
it a more crimson hue. 
