Gold leaf used for kirikane is only 10μm (0,00001 mm) thick! It is made of 24 karat gold with the addition of silver and copper. Gold foil with high percentage of gold in it is often used to reinforce the solemnity. The usual size of square gold leaf is 109x109 mm. Each leaf placed between the sheets of glossy washi paper is so thin that can be blown off with a breath and is carefully handled with a pair of special bamboo tweezers.