Does hard and crumbly finger/toe nails mean in lacking a vitamin or something else?

i was cutting my nail and i noticed thisDoes hard and crumbly finger/toe nails mean in lacking a vitamin or something else?
finger- and toe-nails (and hair) are mostly silicon. Gelatin is good for that (not jello, which no longer uses true gelatin) as well as meats. It could be a lack of silicon/gelatin or a fungus. If you look up what foods contain this and eat more, but nothing improves, you might need something more. Keep in mind that toenails grow slowly and you'll have to wait a couple- three months before your 'new' nails are long enough to judge.