Although Chinese characters can be written with many materials, for the longest period they were written with a brush. The ink was carbon-based. It was moulded before use into an inkstick. This small solid object could be carried easily. To get the ink the writer had to grind the inkstick against an inkstone with some added water. The earliest Chinese inks can be dated back to 12th century BC, with the use of charred (partly burnt) materials and plant dyes. Mineral inks based on graphite were most common. A bit later, soot was used as the carbon source, and animal glue used to bind the ink to the paper (Egyptian ink used gum arabic for the same reason).