metalblocks-1.2.jar is a release file of the Minecraft mod Metal Blocks for Tinker's + Geolosys, made for Minecraft 1.12.2. It was published on December 3, 2020 and is 0.1 MB in size. For the full description, screenshots and every other version, visit the Metal Blocks for Tinker's + Geolosys mod page.
How to install: Put the .jar into the mods folder (.minecraft/mods) and start Minecraft with the matching mod loader profile.