Creating ornamental rings is one of less practiced tradeskills, but it can still bring credits. The catch is that by making rings out of gems that mobs drop or you found in chest, value of item rises and you can sell it to shops for more credits. Of course you need to make rings yourself or find someone to craft them for you for no tip (since it involves quite a bit of clicking, not very likely).
Before we start with the info on how rings are created, let's look how the value of an item increases with tradeskilling (just remember value doesn't equal what you'll get from shop). We'll use QL 200 items:
As shown, with Platinum Ring we can get x12 times initial value or x12 times what we'd get for the gem that's not processed. And of course, more precious the metal used for ring, higher gain in value. (This also works for Shadowland gems. They no longer lose value after you've cut them.)
We'll need x4.1 in Mechanical Engineering and x1.5 in Agility Skills for Silver, x4.8 in Mechanical Engineering and x1.65 in Agility Skills for Gold, x5.5 in Mechanical Engineering and x1.8 in Agility Skills for Platinum.
All that is left is to apply the gem to the Ring. Since it's the ring that sets the final QL, the gem must be within QL 80% of it.
We'll need x4.65 in Mechanical Engineering and x1.72 in Agility Skills for Silver, x4.72 in Mechanical Engineering and x1.77 in Agility Skills for Gold and x5.5 in Mechanical Engineering and x1.93 in Agility Skills for this process.
Applying uncut gem takes a fraction less skill, but since cutting gems needs about same amount of skills as applying them to Rings, you shouldn't have problems one way or the other.So let's check what gems can be used and their value at QL 200 (top QL for most gems, we'll tell when this isn't so):