Metals can be really fascinating…finding out what you can do with them, how they react, creating your own physical objects from raw materials. Working with metals is challenging, fun and sometimes frustrating, but worth the effort because of things you can create with them — useful things, decorative things, and things to wear, like jewelry and hair ornaments.
Pure metals are extracted as ores, meaning they are elements of the Periodic Table. Other metals are alloys, which are metals composed of two or more of the pure metals.
The two main groups of metals are ferrous and nonferrous. Ferrous is from the Latin ferrum, iron. So those in the ferrous category all have iron in them. They include the pure iron and many alloys, such as the many different alloys that are labelled types of gt6steel.
Nonferrous metals, which do not contain iron, fall into three subgroups: precious metals, base metals and alloys. The precious metals you know already, platinum, gold and silver. The base metals are copper, aluminum, lead, tin, nickel and zinc. And finally, the alloys are metals that combine ores within and between these two groups. Such alloys are brass, bronze, pewter, nickel silver (which, by the way, contains no silver), sterling silver and karat gold.
Gold is a lustrous yellow metal. In its natural state, it is too soft for most purposes. Therefore, gold is almost always alloyed with base metals to give it strength. Karat golds are alloys of gold. The higher the karat number, the higher amount of pure gold there is in the alloy.
The melting point of gold is 1945.4oF, 1063oC, facts to file away in your trivia folder, although it is an important piece of knowledge for a jeweler. Gold is naturally found as placer gold in alluvial riverbed soil, as flakes grains or nuggets, or as reef gold, which is gold embedded in a solid matrix of quartz or other rock.
Gold surpasses all other metals in its malleability and ductility. A metal that is more malleable is more easily worked. A metal with high ductility is easily drawn into wire forms or hammered thin in sheet forms. Gold is resistant to ordinary solvents and corrosion, which is why gold found in ancient ruins is usually well-preserved.
As an alloy for jewelry, gold can be combined with copper, silver, nickel and zinc. Each of these alloying metals gives the resulting alloy a particular character and color. Adding platinum or palladium results in white gold, while the addition of more copper to a yellow gold produces a reddish color, often called rose gold.
The karat of an alloy refers specifically to the relative purity of the gold. Pure gold is 24k. At the current (4/07) spot price of $680, referring to something or someone as “worth its weight in gold” is high praise indeed.
karat % gold