WoW! Junior Gemologist
What is a crystal?
by Douglas S. Le Grand G.G.
www.madmarts.com

Lesson 1: What is a crystal?

... Most crystals are naturally occurring; solid, inorganic, (not living,) materials called minerals. Inorganic compounds not found naturally as minerals also form crystals, such as Cubic Zirconium, or CZ as it is most commonly called. Gemstones are minerals that are associated with perfection, transparency, and clarity. Many crystals fit these ideals but most do not. Crystals are solid materials in which the atoms are arranged in a regular pattern. The word crystal is based on the Greek word krystallos derived from kryos, meaning icy cold. In ancient times it was thought that rock crystal, a colorless variety of quartz, was ice that had frozen and would never melt.

States of matter.
... A material can exist as a solid, a liquid or a gas, depending on its temperature. A good example is water. Water is made up of two parts hydrogen and one part oxygen, bound together to form molecules. When you drink a glass of water it is in its liquid state. Go to the freezer and take out the ice try, now you see the chemical compound known as water in its solid state. When you go to your grandmother's house she puts water in a tea pot to make tea. Then she turns on the fire and heats the water until the tea pots starts whistling. What you see coming out is steam, vaporized water in a gaseous state. In the vapor, (steam,) state the molecules move around vigorously; in the liquid state they move slowly; in the solid state, (ice,) they are arranged in a regular order to form crystalline solid.
... Some objects known as crystal, (fine wine glasses,) are glass and not crystalline. Glass has very little crystal structure, and up until recently believed to have no structure at all. Glass is called amorphous, as it cooled down too fast for the atoms to arrange themselves into a regular structure.

Crystal Surprise
... Crystals often occurs in places where you would least expect them. In southern New Mexico, nodules or Thunder Eggs are formed in Rhyolite, in a volcanic vent pipe. When broken open these nodules often reveal crystals. If you take a trip to the west coast, in San Diego they have a beach called Agate Beach next to Carlsbad where you can find cryptocrystalline quartz agate that displays fern-like growths, which are in fact crystalline growths of mineral deposits. Such crystals are called dendrites and are often found lining joints and cracks in rocks.
... Most gemstones are naturally occurring minerals chosen for their beauty, durability and in many instances rarity. Most minerals are inorganic, but what about a pearl? A natural pearl is organic and is formed inside of an oyster when a grain of sand irritates the oyster so much that it grows a protection between itself and the grain of sand. This shield is a mineral crystal, the mineral is Aragonite. The pearl will slowly form this shield until the oyster dies or is harvested by man.
... The best pearls come from oysters and mussels. Pincatada maxima are the largest pearl oyster and are found in the seas of Australia and Malaysia. Man has been harvesting pearls for almost 2000 years in the Persian Gulf and the Gulf of Mexico.
... Today, many pearls are cultured; man places a preformed seed, usually formed from a mussel shell, into a pearl body and let the oyster do its work. This usually takes several years to form a pearl fine enough to be called a gemstone. Pearls come in many colors including blackish, golden, white and gray. Bombay, India has been a center for pearls for centuries.
...Another organic gemstone is the Abalone shell. Shells with brightly colored pinks, blues and greens belong to the genus Haliotas. They are commonly found in American waters and in the seas around New Zealand where they are called paua. There has been inorganic jewelry made since the beginning of time. The oldest necklace found was dated at over 25,000 years old, and was made of fish vertebrae.
... This is the conclusion for lesson one. Next time I would like to go into more depth about the World of Crystals.

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