So..I just asked about a small dark line under my right thumb nail. The picture I attached was not much clear as it is hard to focus on nail..but I have clicked this one so you may get better idea. And ma'am.. even I thought it's a spot but it's a little vertical if I look closely. Though it's not not very dark like pitch black..it could be any dark color like purple brown or even black..so I can't tell exact but it looks dark.. anyway, you decide what it is. Is it serious or Normal?