Materials

True blue jeans are made out of 100 percent cotton, including the threads. Polyester blends are available, however, the over-whelming majority of jeans sold are 100 percent cotton. The most common dye used is synthetic indigo. The belt loops, waistband, back panel, pockets, and leggings of a pair of blue jeans are all made of indigo-dyed denim. Other features of blue jeans include the zipper, buttons, rivets, and label. Rivets have been traditionally made of copper, but the zippers, snaps and buttons are usually steel. Designers' labels are often tags made out of cloth, leather, or plastic, while others are embroidered on with cotton thread.

Jean insulation
Recycled jeans are becoming a popular insulation material (sometimes called Cotton Batt insulation) used in the construction of houses. Due to its low relative synthetic chemical composition and because it is made of recycled materials, it is gaining prominence in green building circles. Like conventional insulation, it moderates heat transfer and reduces sound transfer between floors or rooms. Blue Jean insulation has an R-Value per inch of 3.7 making it a comparable insulator to typical fiberglass batts.