This is what I call an "Industrial block". Industrial blocks are loaded with holes and the side impressions include hexes for making bolts.

Worn edges on a block are not a bad thing. Swage blocks should have rounded edges on all the shapes for two reasons.
1) Forgings should not have sharp corners and dies with corners produce rough choppy forgings.
2) Both anvils and swage blocks need rounded corners to help avoid chipping.

• Solid Cast Iron
• 12 x 12 x 4 inches
• Worn as shown, has some casting defects on the bottom (above)
• WEIGHT: 100 pounds

How to Use a Swage Block The original How-to article for swage blocks by Jock Dempsey, anvilfire guru.