This mod adds Esmeraldite, a toxic gemstone which can be found found in high mountains and caves. Use it to upgrade iron tools or create decorations with it.
You can make Esmeraldite tools and armor by using an Iron tool or armor piece and the amount of Esmeraldite gems needed for the tool/armor (2 for a sword, 5 for a helmet etc.) probably wont get any more updates, probably.
