Hair was valued for sentimental reasons at a time when there were no photographs. In lieu of photographs, young girls kept scrapbooks of their schoolmate's hair, usually with a name and verse to go with it identifying whose hair it was.
Here's a little bit of the history of made-with-hair mourning jewelry from www.victorianhairartists.com :
Jewelry made with hair is dated back to at least the 1600's, when hair bracelets were given as love tokens by both men and women. During this time one was likely to find the hair placed under glass and used as a background for initials or some other personal symbol to the wearer. Hair jewelry stayed popular until the late 1800's. Many people today believe that hair jewelry was made only for the purpose of remembering a deceased loved one. While that was one function of hair jewelry, many pieces were also made for sentimental reasons, as tokens of affection.
Queen Victoria gave pieces of jewelry made from her hair as gifts, many of these pieces were given to her children and grandchildren. Napoleon wore his watch on a chain made from the hair of his wife, Empress, Marie Louise.
There is even a museum and I bet it's worth checking out. It's in Missouri:
Leila Cohoon 's Hair Museum 1333 South Noland Road Independence, MO 64055
I once went to the Polka Hall of Fame in Cleveland- it was great.