Master Bladesmith Wiki

Gems can be slotted into weapons with the appropriate slots. They can be acquired from chests (3 locks) or randomly - with a low chance - from the mining machine.

Currently gems are only cosmetic. It is planned for a future update that they will give bonuses, but specifics are - as of yet - unknown.

There are 3 shapes and 3 colors of gems currently in the game.

List of all gem shapes and colors
Gem Round Square Triangle
Emerald (Green) GemIcon.png Gem 0.png Gem 2.png
Sapphire (Blue) Gem 3.png Gem 4.png Gem 5.png
Ruby (Red) Gem 6.png Gem 7.png Gem 8.png

Not every blade has slots for every shape of gem. The first one that can hold any gem at all is the Short Sword, which can hold two round gems in its pommel.

List of blades that can be decorated with gems (incomplete)
Blade Round gem slots Square gem slots Triangle gem slots
Short Sword 2 none none
Khopesh 1 none none
Cleaver 2 2 none
Pirate Sword 1 none none
Knight Sword none 2 none
Falchion 2 none none
Scimitar 1 none none
Ornate Sword none 4 none
Cursed Sword none 2 2
Split Sword 2 none none
Royal Sword 2 4 2
Angelic Sword none 2 none
Demon Sword none 2 none
Dragon Sword 2 4 2
more to come ... ... ...