The Periodic Table is a list of 108 known elements arrange by atomic number (see Figure 2-6).
Of these, 92 are naturally occurring (prior to development of artificial nuclear research and development).
Rocks are composed of chemical compounds naturally occurring in nature.
In contrast, minerals considered "gems" are, mostly, exceedingly rare.
A rock is a relatively hard, naturally formed mineral or petrified matter; a naturally formed aggregate of mineral matter constituting a significant part of the earth's crust.
Slow processes creating rocks can be inferred by observing reefs growing in the oceans, or sediments being carried by flowing water in streams or moved by waves crashing on beaches.
We can see sediments being deposited, but we cannot see them turning into stone because the process may take thousand or even millions of years.
For example, the element carbon has 3 isotopes: C is unstable and will undergo radioactive decay.
All there isotopes have 6 protons, but have 6, 7, and 8 neutrons, respectively.The lightest element, hydrogen, has one proton, whereas the heaviest naturally occurring element, uranium, has 92 protons. Isotopes are each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties.Some isotopes are not stable and ultimately break down or change in other elements.Stone is another common term used to describe rock. Figure 2-2 shows how minerals can be combined to form different kinds of rocks that form under different environmental conditions.The mineral composition of a rock reflects the physical environment and geologic history where a rock formed.This section presents many basic concepts that are universal to all physical sciences.1. A mineral is a naturally occurring, inorganic (never living) solid with a definite internal arrangement of atoms (crystal structure) and a chemical formula that only varies over a limited range that does not alter the crystal structure.