Sorry, these slates are not invaluable historic relics, but if you want a unique way to hold a cup of your favorite coffee, the World Traveler slate coaster set may be able to catch your eyes.
This is a set of pretty cool drink coasters handmade by Danielle Johnson from Minnesota. The coaster set contains four drink coasters, and as we can see from the images, each coaster is made out of dark grey slate, due to natural causes, each slate coaster varies to some degree, and each slate features a gorgeous postmark from different city for a unique look. Moreover, the slate coaster is sealed with a slate sealant to prevent the ink from fading, and there are 4 soft foam dots on the bottom so you won’t worry about it scratching your desktop.
The World Traveler slate coaster set is priced at $20 USD. If you’re interested, jump to Etsy for more details. Additionally, if you need other options, you might like to check the wooden rustic coaster set and more via “coaster set” tag.