The rubber is often mounted onto a more stable object such as a wood, brick or an acrylic block. It represents official's signature and is unique for every official.
This one Steemit inspired is photorealistic image made in Adobe Photoshop.
It was big challenge to make this. As you can see only for Stamp there's so many Shape layers who all together looks pretty real.
Mark was bit easier to make but it's looks nice on paper.
Tool:
Adobe Photoshop CS6