Antique reference

Many obituaries of Elizabeth Edwards describe her breast tumor as the size of a half-dollar. I used to get a 50-cent piece every week for my allowance, so the image of that coin is deeply embedded in my memory. But I don't think my kids ever saw a half-dollar, and I'm wondering how many other young people are puzzled by this reference. But then how many young people are reading the obituary of a 62-year-old woman who never performed on Dancing with the Stars or starred in Nip/Tuck? Oops, my youthism is showing!