A 0.45g sample of mineral ore is analyzed for chromium and found to contain 0.560mg Cr2O4. Express the concentration of Cr2O3 in sample as a. Percent
b. Parts per thousand
c. Parts per million
d. Parts per billion

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

answerleaving cheese out to get moldy;

you need to stop taking that class