For iron sulfide, two elements (sulfur and iron) are heated together so that they form the compound iron sulfide. Although iron sulfide contains both sulfur and iron, it is not a mixture: it is a pure substance. Both the sulfur and the iron have 'given up' their individual properties to become a compound.
Granite is a hard igneous rock that is mostly made up of feldspar and quartz. Granite has a crystalline structure, and it can have a wide range of colors from grey to pink. The color of a granite rock is dependent upon the composition of minerals.Any igneous rock that contains one fifth of quartz is labeled as granite.ranite is a hard igneous rock that is mostly made up of feldspar and quartz. Granite has a crystalline structure, and it can have a wide range of colors from grey to pink. The color of a granite rock is dependent upon the composition of minerals.
Confidence votes 18. Gneiss is a banded or foliated metamorphic rock, of similar composition to granite. It is very hard and used where granite would be used, some gneisses are used as facing stone on buildings.counter tops.o. Gneiss is a high-grade metamorphic rock. Even if the gneiss  formed from what was originally a fossil-containing rock, the  metamorphism will have destroyed the fossils.