Cymbals comprise an entire family of idiophones that also include gongs, tam-tams, crotales and other similar instruments usually made from bronze. For a long time, China was credited with the development of cymbals, but research suggests that they might have actually been imported from Tibet, Turkey, and India. Cymbal-making has long been a secret art,
and the alchemist Avedis Zildjian (whose name appears on the majority of cymbals in existence) was an early Turkish cymbal maker whose exact formula is still a family secret today. Generally, the best cymbals of the Turkish-variety are 81 percent copper, 19 percent tin with traces of silver and other elements. Chinese cymbals, on the other hand, have a characteristic shape much different than the standard Turkish cymbal. The edge of the cymbal is turned up anywhere form a 1/2" to 2" and the characteristic trash sound of these discs is generated. Zildjian and other major manufacturers have pretty much taken over production of this entire family of idiophones and also create Chinese cymbals.
Types
The types of cymbals a percussionist has at his\her disposal are numerous. The major manufacturers, Zildjian and Sabian, group the majority of their products in to three categories. K Zildjians and HH (Hand Hammered) Sabians are essentially sister cymbals. Both use erratic hammering and are the most expensive, the darkest, the trashiest, and usually the most musical. Jazz and orchestral artists often utilize these cymbals. Their are smaller divisions of the K's and HH's, most noticeably the French, Viennese, and Germanic styles which directly refer to the thickness and weight of the cymbals (lowest and thinnest to thickest and highest respectively). A Zildjians (the "originals") and AA Sabians are machine hammered and are the most frequently found cymbals in schools, drum corps, and most bands. They are a good general cymbals for all around use and are cheaper then K's and HH's. There are also numerous budget lines, and these cymbals, unlike their cast siblings, are cut out of a sheet of bronze and generally sound as cheap as they cost. These include Zildjian "Scimitar" and Sabian "B8" cymbals. These are good for beginning drummers and are often sold in packaged sets. Sizes of cymbals typically range from 6"-24" with extra large and small sizes being offered as custom orders. Gongs can get very large, some several feet in diameter.
A drumset usually has a pair of 14" hi-hats, a 16" crash cymbal, a 20" ride cymbal, and possibly a small 6" splash cymbal. Usually 6-12" cymbals are called splashes, 13"-19" cymbals are called crashes, 18"-24" cymbals are called rides unless they are specifically made for being played as hand cymbals. Two ride cymbals do not make a nice pair of 19" crash cymbals though, and as with any instruments, one can spend a long time picking out a cymbal or a pair of them. A good cymbal lacks definite pitch and is rich in overtones usually. Rock and loud-music specialist usually strive for very high pitches cymbals which cut thought volume with more ease than do the thinner K's and HH's.
The body of a cymbal
The picture here illustrates the main areas of a cymbal. 
Most tam-tams and gongs are a little different in that they have no cup and are basically a flat piece of metal with the edges turned in 90 degrees. The gong pictured above is an opera gong - behind it is a wind gong which has a lot higher overtone series than most tam tams. Although gongs refer to the loose group of tam-tams and gongs together, tam-tams have no definite pitch whereas gongs have definite pitch. Pitched gongs usually have a dome shaped cup in the middle and are usually much smaller than the tam-tams one sees so often in ensembles.
Performance
Cymbals can played many different ways. One can put straps through the holes and play them with one's hands as a pair. One can also play them on a stand with sticks, mallets, brushes or other special beaters. Gongs generally are played with very large and heavy mallets which often use hockey pucks as the core material, with yarn being wrapped around them to eliminate the click sound the raw puck would deliver.
Other Cymbals Types
Crotales, gongs, bell discs, thunder sheets and finger cymbals are all types of cymbal accessories. One of the interesting characteristics of percussion is the fact that instruments are still being created all the time. Cymbal manufacturers have gone a little wild in the past few years creating all kinds of new timbres for use in the percussion ensemble, the drumset, and even the orchestra.
