Open up a new layer sizing it to 512x512 as shown below,
Once this is done you want to fill it black like above the only reason im filling it black is because i want the dark pearl look yous can do whatever color you want once you know what your doing, anyway fill it black lol, you should then go to the ellipse tool and make a round circle on your black layer and colour it whatever colour you want your pearl to be mine is going to be Pink
Step 2: you should now have a black square with a huge coloured circle in it if this is correct your that one step closer click on the effects tab at the top of your page go down to blurs and select gaussian blur for those who do not have this tool you can find it in this free paint.net brush pack at Ed Harvey Effects v 3.5
anyways back to project select the guassian blur and i normally set mine to 127 gives the not to over the top effect, when you select this you should see your circle going blurry wait till its all done you should have somthink like this now
Step 3:
now you should have a black background with a blurry fluffy looking circle on it select the ellipse tool again and circle around the coloured blur making sure you have the lightest part to the north west of your circle your creating when you got it select copy
Step 4:
when youve copied the circle you made open up a completly new layer and paste your pearl on to that then go to the adjustments tab at top and select brightness and contrast and fiddle about with it till you have what you think is the perfect shine i usually go with brightness 20 contrast 25, ok now you should have your pearl all done and you can size it whatever size you want and copy and past as many as you need to create your necklace, braclet or whatever you want to make i played round with a few colours and got these hope this is ok i think its fab for pearls gud luck everyone!