Gem Smithing
Gem Smithing is performed by Rogues using the "Gem Polishing" ability. Gem Polishing allows rogues to polish Beryls, Corals, Rubies, and Talos into higher qualities. When the Gem Polishing ability is active, drop the gem you wish to polish at your character's feet. If successful, the gem will improve in quality from "Fragment", "Uncut", "Flawed", and finally "Finished". When a gem is successfuly polished from Flawed to Finished (regardless of whether it was found Flawed or polished into Flawed), you will gain one rank in Gem Smithing, which will appear in your Legend.
At Gem Smithing level 50, you will gain the "Master Gem Smith" Legend Mark and no longer have a chance of breaking gems when polishing. Polishing gems requires one day of labour. However, there is a percentage chance (equal to your dexterity) that the labour from polishing will be refunded. It is therefore possible to polish any number of gems, without any chance of breaking or labour usage, when you are a Master Gem Smith with a Dexterity of at least 100.
If you're looking to improve your Gem Smithing ability, one strategy is to wait until you have a high amount of Dexterity, and then purchase gems at the Rucesion Black Market to polish, as you will break many purchased gem fragments without using much labour. On the other hand, if your dexterity is low, you may wish to exclusively attempt to polish Flawed Gems, as the only time you gain a legend mark is when successfully polishing a Flawed gem to a Finished gem. Flawed gems can be found while hunting in Temuair, particularly on Grimlocks in Pravat Cave.