I need a piece of advice friends I have purchased a very beautiful and elegant pearl cum blue diamond necklace last year but I am finding it hard to maintain its shine .As the necklace is of gold its getting blacken.I am afraid how its getting black so early?Its a gift from my Husband to me as over Anniversary gift.Please help me retrieve its shine as it was given to me with great love from my husband.I wonder that I rarely use the necklace then also how its loosing its shine?