For about 2 years I have been saving my empty books of gold leaf, most were 23.5ct gold, but also 12ct white, 22ct moon, silver, and other carats.
Here are 382 books which had 25 leaves per book, so 9550 leaves of gold.
Each leaf is 3" x 3" and the thickness is about 4 to 5 millionths of an inch or in metric that is 0.1 to 0.125 millionths of a meter (or micrometers, µm)
1000 leaves has about 16 grams of gold, so gives 152.8 grams, today the market price for pure gold is 27.99 GBP per gram, so a value of 4276.87 GBP
1 book covers about 1.975 sq feet so this gives an area of 754.45 sq feet of gold that I have used to make gilded picture frames in the last two years!
