What mineral property can be used to distinguish between pyrite and chalco pyrite?

Answer 1

Pyrite also known as "fool's gold" is a mineral that has both a different chemical, morphological and physical characteristics than gold. Gold is denser (i.e. the same size of gold is much heavier than the that of pyrite). Gold's average density is 17.64 g/cm3 while Pyrite's density is on average 5.01 g/cm3.

The chemical formulas are different. Gold's chemical formula is "Au" while Pyrite's is and iron sulfate mineral with a formula of "FeS2".

The color is also different, gold appears the color of gold while pyrite is more bronze in color.

The crystallographic form of the minerals also vary.

Gold is a very soft mineral while Pyrite is much harder (gold has a hardness of 2.5 while Pyrite is 6.5). To distinguish between a sample of each, you could scratch the surface of gold using your fingernail which you would not be able to do with pyrite.

You can try to scratch it because pyrite or fools gold much harder then gold so if it doesn't scratch that much it is most likely pyrite or fools gold.

You can tell them apart by looking at their reflection and streak. Also, gold is much more dense than pyrite, so the same volume would 'weigh' about 3.5 times more. Gold has a hardness of about 2.5, while pyrite is about 6 (Gold is softer and more malable).

Streak is used to distinguish between Gold and Pyrite.

Answer 2

Pyrite and chalcopyrite can be notoriously hard to distinguish between. There are several mineral properties that can be used to tell the difference, however. First, chalcopyrite is slightly softer than pyrite (Chalcopyrite has a hardness of 4.0 on the Mohs hardness scale, whereas pyrite has a hardness of 6.0.-6.5). Additionally, chalcopyrite has a lower specific gravity (4.3) than pyrite (5.0). Lastly, chalcopyrite tends to be slightly more yellow than pyrite, which is often a tannish-gold color. This last property is less reliable, however, since color is a matter of perception, and you may not have a sample of each mineral to compare your specimen to.

Answer 3

Color and density are good indicators. Pyrite is gold in color (hence the nickname "fool's gold") and often bears linear striations. Galena is a bluish-silver color and is significantly denser than pyrite.