This topic is about the different skill gains. For every skill you raise, there are different colors to the skill gain. Combat skills and all skills such as exploration, skinning and inscription have a purple skill gain. This means that no matter what you explore, no matter what spell/style you use, no matter what you skin or what you inscribe, you will gain a skill point in the skill. For most other gathering skills and most skills, there are green and orange skill gains. Orange means that it was a guarenteed skill increase, such as You raise your tinkering to 251 of 300. Where as green skill gains are where there was only a chance of gaining a skill point: You raise your tinkering to 252 of 300.