how to cut gems

Yeah it's simple, first you need to have the right crafting level.

~~Gem~~ ~~Crafting Level Required to Cut~~
Uncut sapphire 20
Uncut emerald 27
Uncut ruby 34
Uncut diamond 43
Uncut dragonstone (Members only) 55
Uncut onyx (Members only) 67

Once you have the right level all you need to do is use a Chisel on it, which can be bough from any General Store.

First of all, you will need the correct crafting level. Then, you just need a chisel. Use the chisel on the gem.

The guys above are right once you cut a gem it can sell for alot higher, if you have a higher level you can make sapphire rings, ruby necklaces diamond amulets and emerald bracelets(members only)

You need a chisel, crafting lvl of at 20, and an uncut gem.

fist of all you need a gem.
uncut saphire:20 crafting
uncut emerald:27 crafting
uncut ruby:34 crafting
uncut diamond:43 crafting
uncut dragonstone (members only):55 crafting
uncut onyx (members only):67crafting

then you will need a chisel from any general store or the grand exchange then use the chisel on the uncut gem that you have the correct crafting level for.