I have checked lot of internet forums fir my issue but can't find one , I started noticing this issue around 5 6 years ago, my nails now have become very dull black in colour it remains the same through out the day but sometimes when I feel fresh like after sports or waking up colour be becomes better but the index finger and thumb nail remains the same. I am also having black tint above the nails. And I don't smoke nither drink