I remember when I first discovered that postcards were made out of leather, I thought that was rather unusual. Why would anyone write on and mail something that isn’t paper? How could you write on leather without it ripping? The two leather postcards I have, shown below, are both written with ink on the back and still have the stamp still attached to them. They are a little smaller than standard size. The first is the Public Library in Chicago, and the second is the Chicago Post Office. Both are postmarked in 1906.
One would think that leather postcards are rather expensive to buy because they are less common than normal postcards. However, they can be quite cheap- $2 or $3. Ones that are leather and shaped like something- a glove, maple leaf, or house- seem to go for more than this.
Leather isn’t the only material besides paper used to make postcards. I have a wooden postcard, which is very small, of Fort Dearborn at the Chicago World’s Fair. There are also postcards made out of cork, but I do not have one of those.