Painting Skin, Gold Jewelry, and pearls in Acrylic 

(colors can apply to oils also)

Below are the results of demonstrations I have done in the painting of skin, pearls and gold.  Perhaps you can get some benefit from it if you are painting portraits.  Happy to share what I have learned-- enjoy!

Examine the jewelry (in photo or on model) closely to identify where it glistens and shimmers, and at what angle.  Look for colors within the gold also.

The color and reflections on pearls depend on what colors are around it, especially clothing or skin which it is placed against, and including what kind of direct light is cast.  All reflections should be soft in nature, and not harsh, and follow the curve of the pearl ball.  Remember to also paint any shadows cast by the pearl on fabric or skin to get a 3-dimensional look.

This skin demonstration was painted hurriedly in acrylics in order to be able to mix colors while still wet.  If done in oils of course there would be no rush, as they are slow-drying.  I did not wash my brush between hues, but just wiped it off with a paper towel.  This was done with straight acrylic paint, no water.