Barcelona is the capital and most populous city of the Autonomous Community of Catalonia and the second largest city in Spain, with a population of 1,605,602 in 2006, while the population of the Metropolitan Area was 3,161,081. It is the central nucleus of the Urban Region of Barcelona, which relies on a population of about 5.5 million. It is located on the Mediterranean coast between the mouths of the rivers Llobregat and Besòs and is limited to the west by the Serra de Collserola ridge. Barcelona is a major economic centre with one of Europe's principal Mediterranean ports, and Barcelona International Airport is the second largest in Spain. Founded as a Roman city, Barcelona became the capital of the Counts of Barcelona. After merging with the Kingdom of Aragon, it became one of the most important cities of the Crown of Aragon. Besieged several times during its history, Barcelona is today an important cultural centre and a major tourist destination and has a rich cultural heritage. Particularly renowned are architectural works of Antoni Gaudí and Lluís Domènech i Montaner that have been designated UNESCO World Heritage Sites. The city is well known in recent times for the 1992 Summer Olympics.

Loose Stones

Some people purchase loose stones for jewelry making, while others do so for investment purposes. Still others are looking for the perfect stone to have made into a piece of jewelry by a custom jeweler. Most gemstones are minerals, but some rocks such as lapis lazuli and organic materials like pearls or amber considered as such. Today, four stones are precious stones: diamond, emerald, ruby, and sapphire. Everything else falls under the category of semi-precious stones. When purchase loose stones, obviously should only deal with a reputable jeweler that trust, online or in person. Always get a certificate from the seller and be sure exactly what are purchasing. Diamonds are the only gemstones that have a universally accepted grading system based on the concept of the four C’s: color, cut, carat, and clarity. Clarity is determined by placing the diamond under 10X magnification. However, cut is most important for the value of a clear diamond, because without the proper cut, the diamond will not sparkle, as it should. Clarity and color are next in importance. All other gemstones grade with the naked eye. The quality of all colored stones based on the clarity and brilliance of the stone’s color, which divided into three parts: hue, saturation, and tone. Hue refers to the stone’s color, which produced in the following spectral hues: red, orange, yellow, green, blue, violet, purple and pink. Purple and pink are spectral hues, as purple lies halfway between red and blue, and pink is really a lighter shade of red. Natural stones seldom have pure hues, so these are into primary, secondary, and sometimes tertiary hues. Saturation refers to the clarity of color, or the stone’s freedom from brown or grey hues.