Hobbies And Interests
Gold
Gold has many colors: yellow gold, rose gold and white gold. The differences in the colors of gold are governed by the metals used in the mixing of the gold. The hue of any gold will not disintegrate over time.
Yellow gold is a mixture of pure gold and metals such as copper and zinc. The copper content determines the color of yellow gold. For instance, 24-carat (ct) gold is pure gold whereas 18-ct gold has 18 parts of pure gold and six parts of copper and zinc. Nine-ct cold has nine parts of pure gold and 15 parts of copper and zinc.
Rose gold has a rose-reddish tinge because it has a higher copper content than yellow gold.
White gold is a blend of pure gold and white metals such as silver and palladium.
Gold has been used, historically, as a means of exchange. Gold is also used in jewelry making, electronics and in dental work.
Silver
SIlver is a very soft metal and cheaper than other precious metals like gold and platinum. Silver will easily tarnish and lose its characteristic luster. Therefore, silver requires regular cleaning or must be protected.
Silver is used in silverware, jewelry, photography, silver service appliances and other applications where appearance is paramount.
Platinum
Platinum is a silver-white metal used in jewelry and in some electrical and laboratory apparatuses. It is very durable and retains its luster and so does not need to be coated. Platinum is a very dense metal, so a platinum ring will feel bulkier than an 18-ct gold ring. Platinum is also significantly pricier than gold, with a platinum ring costing roughly twice the price of an 18-ct white gold ring.
Ruthenium and Rhodium
Both ruthenium and rhodium are hard silvery-white metals, with rhodium being particularly dense.
Ruthenium does not react with air, water and acids but does react with molten alkali and halogens and can oxidize explosively.
Rhodium is used mainly for plating, largely white gold jewelry, and has similar properties to platinum. Plating with rhodium gives white gold a whiter and brighter appearance.
Palladium
Palladium is a rare silvery-white metal resembling platinum. It does not need any plating to enhance its white appearance since it has its own natural brightness. It is pliable, and, like gold, can be beaten into a thin leaf. Palladium is strongly resistant to corrosion in air and to the action of acids and does not tarnish easily. Remarkably, it can absorb up to 900 times its own volume of hydrogen, expanding visibly.
Palladium is used in catalytic converters for automobiles, in making watches, in dentistry and in industry.
Titanium
Titanium is a hard silver-gray metal used in strong, light, corrosion-resistant alloys. It is the hardest natural metal in the world yet is very lightweight. Titanium has excellent strength and also has a high strength-to-weight ratio.
Osmium and Iridium
Osmium and iridium are hard, very dense silvery-white metals. Both were discovered at the same time by Smithson Tennant in the residue remaining when crude platinum was dissolved by aqua regia--a mixture of hydrochloric acid and nitric acid.
Osmium is the densest of the elements, and iridium comes a second. Osmium has the highest melting point and the lowest vapor pressure of the platinum group metals. Iridium is very stable and does not react much.
Osmium is principally used in conjunction with other platinum group metals to form other alloys. It is also used to make an alloy used in surgery. Iridium's main use is as a hardening agent for platinum alloys.