Fineness

The fineness of a precious metal refers to the ratio by weight of the primary metal to any added base metals or impurities. Many precious metals are used in the form of alloys. Other metals are added to increase hardness, to make the metal more practical for use in such items as coins and jewelry, or to decrease the cost of the alloy. For example, copper is added to the precious metal silver to make a more durable alloy for use in coins, housewares and jewelry. Coin silver, which was used for making silver coins in the past, contains 90% silver and 10% copper, by mass. Sterling silver contains 92.5% silver and 7.5%, by mass, of other metals, usually copper.

Various ways of expressing fineness have been used and two remain in common use: millesimal fineness expressed in units of parts per 1,000 and karats used only for gold. Karats measure the parts per 24, so that 18 karat = 18/24 = 75% and 24 karat gold is considered 100% gold.

Millesimal fineness

Millesimal fineness is a system of denoting the purity of platinum, gold and silver alloys by parts per thousand of pure metal by mass in the alloy. For example, an alloy containing 75% gold is denoted as "750". Many European countries use decimal hallmark stamps (i.e. '585', '750', etc.) rather than '14K', '18K', etc., which is used in the United Kingdom and United States.

24K

24K can refer to:

24K (radio show)

24K Weekend (formerly 24K Saturday, 24K Friday & 24K Experience) was a weekly radio show of 99.5 RT featuring 1970s, '80s and '90s music.

Background

In 1989, 99.5 RT's 24K began as 24K Saturday, as an answer to Magic 89.9's Friday Magic Madness, to avoid competition with the latter. Unlike Madness, 24K also plays hits they played first since RT's inception. Sooner, around 1995, 24K gained popularity, it moved to Friday as 24K Friday, in order to compete with Madness. In 2004, 24K was put off the air for some reasons. However, due to popular demand, less than a year, it was back on the air. 24K was last heard on December 15, 2006, following RT's last broadcast two days latter. However, it continued until December 29, without stingers.

In September 2007, 99.5 Hit FM revived 24K Friday, but this time playing only late 70s & 80s every Fridays. However, it only lasted until November 7, 2007, when 24K was replaced with No. 1 Hit Weekend (which began airing a week after 24K's revival & played only 90s). In January 2008, Hit revived once again the 24K brand as 24K Experience, but this time playing 70s & 80s every Sunday afternoons. It lasted until March 16, 2008, before Hit FM rebranded to Campus FM.