2.1 Carrollite has the formula Cu(Co,Ni)2S4
- All matter, including mineral matter, is made of elements.
- 8 to 10 elements account for most of Earth’s mass but the elements are distributed unevenly.
- The Periodic Chart of the Elements orders elements by their atomic number and groups elements with similar properties.
- Elements with similar properties may substitute for each other in minerals and many minerals have variable compositions.
- Ionic, covalent, or metallic bonding are most common in minerals.
- The kind of bonding affects mineral properties.
- We describe mineral compositions by giving weight %s of the elements or oxides present.
- Weight % values can be normalized to give chemical formulas.
- Although 1000s of minerals are known, only a small number are common.