In creating jewelry, gemstones, coins or other precious items are often used and they are typically set into precious metals. Alloys of nearly every metal known have been encountered in jewelry. Bronze was common in the Roman times. Modern fine jewelry usually includes gold, white gold, platinum, palladium, titanium or silver. Most contemporary gold jewelry is made of an alloy of gold, the purity of which is stated in karats, indicated by a number following by the letter K. American gold jewelry must be of at least 10K purity or 41.7% pure gold. It can go up to 18K or 75% pure gold. Higher purity levels are less common with alloys at 22K or 91.6% pure gold and 24K which is 99.9% pure gold. This is usually too soft for jewelry used in America and Europe. These higher purity alloys, however are widely used across Asia, the Middle East and Africa. Platinum alloys range from 900 or 90% purity 950 or 95% pure. The silver used in jewelry is usually sterling silver, or 92.5% fine silver. In costume jewelry one can find stainless steel.
Other common materials include glass, enamel, wood, shells, bone, ivory, and natural or polymer clay. Hemp and other twines can be used to create jewelry that has more of a natural aesthetic feel. The beads are also recently used in jewelry. Feed embroidery, a popular type of handiwork during the Victorian era, is enjoying a renaissance in modern jewelry making. Beading or beadwork has also been very popular in many African and North American cultures.
Diamonds were first mined in India (read the article - Diamonds). Now Australia, Botswana, Russia and Canada are ranked among the primary sources of gemstone diamond production. Diamonds undermine during recent civil wars in Angola, Ivory Coast, Sierra Leone have been labeled as blood diamonds (read more about "Blood Diamonds" in Wikipedia) when they are mined in a war zone and sold to finance and insurgency.
The British crown jewels contain the Cullinan Diamond part of the largest gem quality rough diamond ever found at 3106.75 carats.
Other gemstones and precious or semi precious stones (read the article - The Most Popular Gemstones) are also used for jewelry among them are:
Amber - an ancient organic gemstone composed of tree resin that is hardened over time.
Amethyst - historically been the most prized gemstone in the courts family, treasured for its purple hue.
Emerald - one of three main precious gemstones along with rubies and sapphires known for their fine green color.
Jade - can come in a number of colors and closely linked to the Asian culture.
Jasper - comes in a variety of colors and interesting patterns.
Quartz - a crystal lien gemstone of various colors and sizes.
Ruby - known for their intense red color.
Sapphire - most popular form of the sapphire is blue.
Turquoise - found only in a few places on earth main region being Southwest United States.