crude oil is commonly extracted simply by drilling into the ground in the exact
position where the oil is found.
2. Coal- coal is a sedimentary/metamorphic rock produced in swamps where there
is a large-scale accumulation of organic matter from plants. As plants die, they
decay and accumulate to first become peat. Compaction of the peat due to burial
drives offvolatile components like water and methane, eventually producing a
black- colour organic- rich coal called lignite. Further compaction and heating
results in a more carbon- rich coal called bituminous coal. If the rock becomes
metamorphosed, a high-grade coal called anthracite is produced. However, if
temperatures and pressures become extremely high, all of the carbon is
changed to graphite. Graphite will burn only at high temperatures and is
therefore not useful as an energy source. Anthracite coal produces the most
energy when burned, with less energy produced by bituminous coal and lignite.
3. Natural gas- natural gas is derived from marine plants and animals; that is by a
combination of sedimentary processes) which trap and bury plant and animal
remains, and then metamorphic processes which heat and change the plant and
animal remains into deposits of oil and gas.
4. Gold- gold is a rare, valuable and durable precious metal with a versatile use;
gold is relatively heavy and can be made into a wide range of intricate jewelry
designs. Apart from being used as jewelry, gold is also used in dentistry,
medicine, coins, and applications for the aerospace industry. However, gold has
a high corrosion resistance and will not tarnish from everyday use, thus making it
ideal for jewelry. Gold is commonly alloyed with other metals to increase its
strength and durability, as well as to alter its hue. Gold is available in various
degrees of purity. Yellow gold is seen most often, but white gold (gold mixed with
palladium, nickel and silver) is also popular in some parts of the world, especially
for bridal jewelry.
5. Silver- silver is a light precious substance used for making jewelry, cell phone
covers, fine silverware, coins and photography. Because of its versatility,
availability, affordability and appeal; it is used for different things and it is very
bright, durable and easy to work with. Silver also is substantially cheaper than
gold or platinum.
6. Platinum- platinum is the most precious and durable of all metals used in jewelry
industry; it is very pure and it is rarer, denser and stronger than gold or silver.
Because of its purity, it doesnt tarnish or fade after much use, and its extremely
durable. Platinum has a deeper and more luminescent white hue than either
white gold or silver. Platinum is the traditional metal for heirloom-quality jewelry.
It's a natural partner for a fine white diamond.
7. Lead- it is a bluish-white soft malleableductileplastic, or inelastic heavy metallic
element found mostly in combination and its used especially in X-ray and gamma
radiation shielding, pipes, cable sheaths, batteries, solder, and shields against
radioactivity, ceramics, weights, and ammunition.
8. Gypsum- this is a soft white or grey mineral consisting of hydrated calcium
sulphate. It occurs chiefly in sedimentary deposits; it is used for making cement,
plaster of Paris, fertilizer, wallboard, and glass.