Jewelry School-Gold
Gold is a precious metal with a dazzling golden metallic luster. Pure gold has a specific gravity of 19.3 and a melting point of 1063°C. It has a soft texture and good toughness, excellent ductility and conductivity, and stable chemical properties. It is only soluble in aqua regia or potassium sodium cyanide solution and can be easily processed into various shapes. Gold is a precious metal with a dazzling golden metallic luster. Pure gold has a specific gravity of 19.3, a melting point of 1063°C, soft texture, good toughness, excellent ductility and conductivity, stable chemical properties, only soluble in aqua regia or potassium sodium cyanide solution, and easy to process into various shapes . Therefore, it has been used to make decorations since ancient times. The gold content of gold is usually also referred to as the fineness or purity of gold. The jewelry industry is represented by gold, au or g before its purity per thousand (k number). For example, gold 750, au750 or g18k is divided into 999, 990, 916, 750, 585, 375 according to the purity thousand fraction, and the corresponding k numbers are expressed in order of thousand pure gold, pure gold, 22k, 18k, 14k, 9k. Gold overview Gold is also called gold, English gold, chemical symbol au, atomic number 79, it is an orange-yellow metal substance. In nature, gold generally exists as a simple substance. 1. The density of gold is very large. Under normal temperature and pressure, the density of gold is 19.32 g/cm3, which is nearly 20 times that of water and more than three times that of iron. 2. The melting point and boiling point of gold are very high. The melting point is 1064.43°C and the boiling point is 2808°C. As the saying goes: “real gold is not afraid of fire” refers to this. 3. The Mohs hardness of gold is 2.5, which is not comparable to the hardness of human nails. up and down. 4. Gold has good toughness and ductility. One gram of pure gold can be drawn into filaments of more than 3000 meters, or forged into gold leaf of 9 square meters. 5. Gold has high stability and strong corrosion resistance. It is insoluble in other acid and alkali solutions except for aqua regia. The gold burial objects unearthed in ancient tombs are as bright as new despite thousands of years of wind and rain. Purity The fineness of gold is the purity of gold, which refers to the content of gold elements in gold items. There are two popular methods for expressing the fineness of gold: 1. K gold law people call gold with a gold content of 100% as 24k gold. The relationship between the number of k and the gold content is lku003d4.1666%. According to this formula, the gold content of 18k gold is 75%, 14k gold contains 50% gold, and 9k gold contains 37.5% gold. 2. Proportion method The gold content in gold items is expressed in percentages and thousand fractions. For example, au99.95 is gold with a gold content of 99.95%, and au999.5 is gold with a gold content of 999.5‰. Color The color of gold is determined by two factors: 1. The type of synthetic metal it contains 2. The percentage unit of each metal. Gold measurement units vary in different parts of the world. Common gold measurement units are as follows: 1. The troy ounce system in Europe and America. 1 troy ounce u003d 31.103495 grams 2. The two systems of balance in Hong Kong, Japan, and ancient China. 1 Sima Liang u003d 37.42849791 grams 1 Japanese tael u003d 3.75 grams 1 Shijin u003d 16 small Liang u003d 500 grams, 1 tael u003d 31.25 grams 3. City system of measurement unit. Now Shanghai Gold uses grams as the unit. 1 catty u003d 10 taels u003d 500 grams 4. South Asia, New Delhi, Karachi, Mumbai, etc. Tora weighs 1 Tora u003d 11.6638 grams. Maintenance Remember: Keep your gold jewelry away from corrosive chemicals such as chlorine and cleaning agents to reduce daily routine The wear and tear can extend the color life of gold. The method of cleaning gold is as follows: Use soap and warm water solution, and use a soft brush (bald hair is better) to gently clean the gold. Store the gold in a soft cloth bag or original box to protect them from being exposed to the erosion of everyday substances. Please click to browse our charming gold jewelry. Previous: Interpreting the gold price trend from the time period Next: 20 facts about gold
