It is not true...
if copper is ingested it can cause a blood disease.
In ores. Copper ores are found in various parts of the world. Copper can be found as a metal in the ground. Normally, it is green on the outside. Most copper is not as a metal but in chemical compounds. Chalcopyrite is the most common copper ore. It is a mixture of pyrite and copper sulfide. Copper is found in small amounts in living things. Some mollusks and arthropods have blue blood because they have copper in their blood. Animals such as humans and other mammals have red blood because it contains iron. Copper is purified by electrolysis. Electricity is passed through solutions containing copper compounds, such as copper sulfate - sometimes spelt sulphate. Pure copper forms on the negative electrode.
Iron if it's a hemoglobin based blood cell (then the blood is red). If it's hemocyanin then it's copper and the blood will be blue. Like the people of Pandora.
there is copper in its blood
Octopuses have copper and magnesium in their blood.
copper
Copper is a metal. It is also considered as a mineral as well. You can find traces of copper in your blood.
albumin
blood
one way is that their blood is blue because the blood has copper in it copper is a metal
Copper ions in your blood are nefro-toxic (kidney's)
That's just nature. If it were'NT nature i'd have like pink-blue blood and you would have like black blood....