What are Wheat Chain and Rope Chain?
Wheat chain and rope chain have the appearance that the links are braided or twisted together, rather than simply linked. Wheat chain is also found under the name spiga or espiga (Spanish for wheat) chain.
It seems that there are many ways of making a chain that looks like growing grains of wheat. Some vendors claim that their wheat chain is made from 4 woven strands of wire. Others say that wheat chain is formed of narrow, long tear-drop-shaped links. Another source says wheat chain uses oval and twisted (like curb chain is twisted) links that interconnect, and this seems to be the most common type of wheat chain. In general, wheat chain does not move as much as simpler chains like curb and rolo chain because the links are so narrow and hold so many other links, that movement is restricted.
Some people call wheat chain, spiga chain (espiga is the Spanish word for wheat). It seems when people refer to spiga chain, this chain is made of figure-8 links linked together, giving it an even more intricate, braided appearance than wheat chain.
Rope chains typically looks like two strands or coils of wire that have been twisted together, also called a double helix. This is a popular chain style for men's jewelry, and it is usually quite thick. Some of the links may have flat sections, giving a faceted effect: this is called diamond-cut rope chain. The links are typically oval or round, and rather than being twisted or spiraled together, the links are carefully joined to the link across from them. This is a very delicate process, and even though automatic rope chain machines have been around since the 1930s, still today many of the rope chains on the market are handmade. Italy provides much of the world's machine-made chain. For a detailed drawing of a rope chain, check out this PDF copy of a patent filed on fine jewelry rope chain.