Here are my nuggets
Pearls can be worn by anybody but especially those born in June or under the zodiac sign of Cancer (as can moonstones) like my mother who always wears pearls.
Pearls worn should never be whiter than one's teeth
Pearls only turn into tears if you don't wear them (they lose their sheen). Once owned pearls are meant to be worn.
Opals are bad luck (my grandmother) but then she had a natural pearl E-ring LOL
Never wear a ring on your wedding ring finger if single (I think that was because any would-be suitor would think you're 'taken')
If you put on a ring up-side-down or facing the 'wrong' way don't change it all day or you'll turn protective forces against you
Horse-shoe charms should be worn U
Never wear faces or people up-side-down in a locket
My (Pakistani) friend black jewellery including onyx are bad luck because the absorb bad energy whereas anyone can wear clear and white stones as they reflect and bounce back energy. He said people go to great lengths to divine which stones work for them and when, seeking consultations with specialists.
I know some consider sapphires completely unlucky, however in the Middle-East blue is the most protective and healing colour