The purple gem that you see in the back of the course is a special gem that will give you 2000 points if you have your ball roll over it. However, if you aren’t going to pass it on your normal route to the hole, don’t bother with it. Chances are that the extra shots that it will take you to grab it will be less than the points you’ll earn if you just go straight for the hole. If you get it, great—if not, if your opponent tries to go for it, chances are you’ll get an eagle and they get par, and by extension, get less points than you.
The little gold coins littering the course are worth 100 points each when your ball rolls over them. Like the gems, they’re not worth grabbing except for those that you will earn on your path to the hole. Don’t focus on them—they’re not important as getting to the hole as quick as possible.