Gemstones have always fascinated mankind. In former centuries they were reserved for the ruling classes, today most people can afford beautiful stones for jewelry and decoration. Today, the gemstone is viewed as a capital investment, it is known that wealth kept in gems has survived the pressures of inflation better than most investments.

The first known gems were amethyst, rock crystal, amber, garnet, jade, jasper, coral, lapis, lazuli, pearl, serpentine, emerald, and turquoise. Years ago, these stones were held by the wealthy and had many different purposes. The rulers sealed documents with jewel-encrusted seals, which were a sign of their wealth and power. Gems also held a spiritual aura and were worn as ornaments and charms. They were thought to protect against ghosts. They could fend off evil, preserve health, fight off poisons, the plague, and they also were thought to lead sailors home. Prior to the 19^th century, gemstones were sometimes used as medicine. They were either placed on the ailing part of the body, the stone was powdered and eaten, or their mere presence was sufficient enough to cure. If the gems failed to heal, they were thought to be not genuine. Since the stones were thought to have supernatural powers, they were also linked with astrology and allocated to the different signs of the zodiac. This led to the birthstones, a different stone for each month. Finally, gems have had a place in religion. They are used in the breastplate of the high priest of Judea as well as in the tiara and miter of the Pope and Bishops.

With minerals and gemstones, hardness refers to scratch hardness and cutting resistance. Friedrich Mohs invented the hardness test. He defined scratch hardness as the resistance of a mineral when scratched with a pointed testing object. He determined stones with scratch hardness 1 and 2 are soft, 3 to 6 medium hard, over 6 hard. This use to be of great importance in determining the gemstones. Today, it is mainly used by collectors to determine the nature of the stone. Gemologist now use optical testing methods to avoid damaging the gem. Following is a chart of the relative and absolute hardness scale for different gems.

Following are some stones that we will be discussing in more detail in our report.

Pearls (Mohs’ hardness: 3-4) have been regarded as one of the most valuable gem materials. They have been used for ornamentation for 6000 years. In 2500 BC, there was a substantial pearl trade in China. Pearls are also popular because they do not require any processing. In their natural state they show their full gloss.

Amber (Mohs’ hardness: 2-2 ½ ) is the fossilized, hardened resin of the pine tree, it is know as the "Gold of the North" and is the earliest-used gem material of all. Amber has been used since prehistoric times for jewelry and religious objects, accessories for smokers, also as a cure for various illnesses. Today it is used for ornamental objects, ring stones, pendants, brooches and necklaces.

Emerald (Mohs’ hardness: 7 ½ - 8) means "green stone" and in the ancient times referred to all green stones. Emeralds belongs to the beryl group, being the most precious of the group. The most desired color is a deep green which is the most valuable. Emeralds are formed by rising magma and metamorphism.

Sapphire (Mohs’ hardness: 9) is a name that use to be applied to various stones. Around 1800, it was recognized that sapphire and ruby are gem varieties of corundum. Today corundums of all colors except red are called sapphires, red varieties are called rubies. There is no definite distinction between ruby and sapphire.