Precious Metals - Platinum Gold Silver Pladium Facts

Gold (pronounced /ˈɡoʊld/) is a chemical element with the symbol Au (from its Latin name aurum) and atomic number 79. It is a highly sought-after precious metal which, for many centuries, has been used as money, a store of value and in jewelry. The metal occurs as nuggets or grains in rocks, underground "veins" and in alluvial deposits. It is one of the coinage metals. Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold has a bright yellow color traditionally considered attractive.

Because of the softness of pure (24k) gold, it is usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Alloys with lower caratage, typically 22k, 18k, 14k or 10k, contain higher percentages of copper, silver or other base metals in the alloy.

White gold is an alloy of gold and at least one white metal, usually nickel or palladium. Like yellow gold, the purity of white gold is given in carats. White gold's properties vary depending on the metals and proportions used. As a result, white gold alloys can be used for different purposes; while a nickel alloy is hard and strong, and therefore good for rings and pins, gold-palladium alloys are soft, pliable and good for white gold gemstone settings. The highest quality white gold is usually at least 17 carat, and made up of gold and palladium, sometimes with trace levels of platinum for weight and durability, although this often requires specialized goldsmiths. While some higher-quality white gold alloys retain their shine and lustre, most will be coated with a very thin layer of rhodium. This gives the naturally more-dull white gold a shine comparable to platinum or silver; however the rhodium may wear off over time.

Rose gold is a gold and copper alloy widely used for specialized jewelry due to its reddish color. It is also known as pink gold and red gold. Because it was popular in Russia at the beginning of the nineteenth century it is also known as Russian gold, although this term has become somewhat rare. Since it is an alloy, there is no such thing as "pure rose gold"; pure gold is yellow and pure copper is reddish. Although the names are often used interchangeably, the difference between red, rose, and pink gold is the copper content: The higher the copper content, the stronger the red coloration. A common alloy for rose gold is three-quarters gold and one-quarter copper by mass (i.e. 18Kt)..

Platinum (pronounced /ˈplætɪnəm/) is a chemical element with the atomic symbol Pt and an atomic number of 78. It is in group 10 of the Periodic Table of Elements. A heavy, malleable, ductile, precious, gray-white transition metal, platinum is resistant to corrosion and occurs in some nickel and copper ores along with some native deposits. Platinum is used in jewelry, laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices.
Platinum is an extremely rare metal, occurring as only 0.003 ppb in the Earth's crust, and is 30 times rarer than gold. If all the world's platinum reserves were poured into one Olympic-size swimming pool, it would be just deep enough to cover one's ankles. Gold would fill more than three such pools.

When pure, the metal appears greyish-white and firm. The metal is corrosion-resistant. The catalytic properties of the six platinum family metals are outstanding. For this catalytic property, platinum is used in catalytic converters, incorporated in automobile exhaust systems, as well as tips of spark plugs. Platinum has a cubic crystal structure. Platinum's wear- and tarnish-resistance characteristics are well suited for making fine jewelry. Platinum is more precious than gold. The price of platinum changes along with its availability, but its price is normally more than twice the price of gold. In the 18th century, platinum's rarity made King Louis XV of France declare it the only metal fit for a king.

Palladium (pronounced \pe-‘lä-dē-em\) is a rare and lustrous silvery-white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the asteroid Pallas, which in turn, was named after the epithet of the Greek goddess Athena, acquired by her when she slew the giant Pallas. The symbol for palladium is Pd, and its atomic number is 46. Palladium, along with platinum, rhodium, ruthenium, iridium and osmium form a group of elements referred to as the platinum group metals (PGMs). PGMs share similar chemical properties, but palladium is unique in that it has the lowest melting point and is the least dense of these precious metals. Incredibly, when palladium is at room temperature and atmospheric pressure, it can absorb up to 900 times its own volume of hydrogen, which makes palladium an efficient and safe storage medium for hydrogen and hydrogen isotopes. Palladium is also tarnish resistant, electrically stable and resistant to chemical erosion as well as intense heat.

Palladium is a soft silver-white metal that resembles platinum. It is the least dense and has the lowest melting point of the platinum group metals. It is soft and ductile when annealed and greatly increases its strength and hardness when it is cold-worked. Palladium dissolves slowly in sulfuric, nitric, and hydrochloric acid.[3] This metal also does not react with oxygen at normal temperatures (and thus does not tarnish in air). Palladium heated to 800°C will produce a layer of palladium(II) oxide (PdO). It lightly tarnishes in moist atmosphere containing sulfur.
Palladium itself has been used as a precious metal in jewelry since 1939, as an alternative to platinum or white gold. This is due to its naturally white properties, giving it no need for rhodium plating. It is slightly whiter, much lighter and about 12% harder than platinum. Similar to gold, palladium can be beaten into a thin leaf form as thin as 100 nm (1/250,000 in).[3] Like platinum, it will develop a hazy patina over time. Unlike platinum, however, palladium may discolor at high soldering temperatures, become brittle with repeated heating and cooling, and react with strong acids.[citation needed] It can also be used as a substitute for nickel when making white gold. Palladium is one of the three most popular metals used to plate gold, making white gold.[11] (Nickel and silver can also be used.) Palladium-gold is a more expensive alloy than nickel-gold, but it's naturally hypoallergenic and holds its white color better.

Silver (pronounced /ˈsɪlvɚ/) is a chemical element with the symbol "Ag" (Latin: argentum, from the Ancient Greek: ἀργήντος - argēntos, gen. of ἀργήεις - argēeis, "white, shining" ) and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. It occurs as a pure free metal (native silver) and alloyed with gold, as well as in various minerals, such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc mining. Silver has been known since ancient times and has long been valued as a precious metal, used to make ornaments, jewellery, high-value tableware and utensils (hence the term "silverware") and currency coins.
Silver is a very ductile and malleable (slightly harder than gold) monovalent coinage metal with a brilliant white metallic luster that can take a high degree of polish. It has the highest electrical conductivity of all metals, even higher than copper, but its greater cost and tarnishability have prevented it from being widely used in place of copper for electrical purposes.

A major use of silver is as a precious metal and it has long been used for making high-value objects reflecting the wealth and status of the owner. Jewellery and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. Sterling silver is harder than pure silver and has a lower melting point (893 °C) than either pure silver or pure copper. Britannia silver is an alternative hallmark-quality standard containing 95.8% silver, often used to make silver tableware and wrought plate. With the addition of germanium, the patented modified alloy Argentium Sterling Silver is formed, with improved properties including resistance to firescale.