The ? Wear did my title go

It sit on the ground everybody see it but most people don’t talk about it. But most people see one of them every day some are of them are smooth some of them are sharp some of them are very very very very very very very very very very very very very very hard. So if see the thing I am talking about pick one up and feel it to tell if it’s smooth, sharp or very very very very very very very very very very very very very very very very very very very very very very very hard?