Well, the site doesn't say how or with what, but it does look like it's done with sea glass and wouldn't it be cool to try to do this?!
Nature always finds a way.
Sea glass bowl, get see glass there https://www.etsy.com/listing/456328736/sea-glass-sea-glass-collection-wedding?ref=related-6
Using the right tools can help make hand lettering a lot easier. These are the best markers, pens, and tools for hand lettering
My favourite photo on the Internet
Shiba Inu Maru Loves To Sleep With His Little Stuffed Polar Bear Toy
Cactus Print Illustrated Set