Page 6 - Curriculum Visions Dynamic Book

Copper ores
Copper is a metal that has been deposited
from hot sulphur solutions, created as volcanoes were erupting. The hot solutions concentrated the copper by up to a thousand times more than would be normally found in rocks. The resultant enriched rocks are called copper ores.
As the hot fluid made its way from magma chambers through cracks and fissures in the rocks, copper ores were deposited in narrow veins.
The island of Cyprus in the Mediterranean Sea is one such ancient volcanic area. The ancient Romans mined the ore there.
The Romans only mined deposits of native copper, which is copper metal that is not bound up in any compound. This pure form of copper was very easy to work and did not need refining. However, most copper occurs as compounds, especially as sulphides, and because they need to be refined, they have only begun to be used relatively recently.
Chalcopyrite and bornite
Chalcopyrite and bornite are minerals containing both copper and iron sulphides. They are the source of half of the world’s copper ores.
Chalcopyrite is a brassy-coloured mineral,
while bornite is often a rich peacock-blue (in fact
it is often called peacock ore). They are formed during intense volcanic activity, when hot liquids were pushed through fissures in the rocks, cooling and solidifying to give minerals with a high metal content. Silver and gold were formed in much the same way, and for this reason the coinage metals are often mined together.
The sample shown here is made mainly of bornite, but if you look closely you will see the gold speckles of chalcopyrite as well.
 A piece of bornite or peacock ore with speckles of chalcopyrite.
 A piece of chrysocolla.
Chrysocolla
Copper silicate and
copper carbonate have a characteristic green colour. Compare this picture to the copper carbonate patina on the Statue of Liberty on page 4. The mineral shown here is called chrysocolla, a copper aluminium silicate.
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