The tree used to make purple sweet potato bracelets is called purple heart wood, also known as purple basil wood and violet wood. The wood is strong, heavy and hard, and shrinks when it dries. It is mainly produced in South America. It is resistant to decay and difficult to dry. Batik can keep the wood blood red.

The purple heart wood is strong, heavy and hard, and shrinks when it dries. Air-dried density: 0.88g/cm3. It is blood red when newly opened, and slightly difficult to process purple after oxidation. It has good properties such as planing, cutting, coloring, gluing, polishing, and painting; it dries slowly, and has slight cracking and warping. It has a fine structure, attractive color, gloss, no special smell, and the texture is usually straight, wavy or staggered. The wood is heavy to very heavy, strong, very resistant to decay, acid, termite and borer damage.

It is mainly distributed in South America and Africa. It is light brown, and will gradually oxidize to purple red, dark purple to purple brown. Because of its natural and unique purple color, it is extremely rare and is deeply favored by people. Just like black tulips and purple roses, it is very rare and is called "violet in wood". It is sought after in the European and American markets and is a precious decorative material and handicraft material.

Purple heart wood has beautiful color, and the wood is relatively smooth, with a polished effect. The wood is hard and not easy to shrink. It is a better raw material for making bracelets. The longer the bracelet made of purple heart wood is worn, the more oily and smooth its appearance will be, the darker the color will be, and the higher its value will be.