These can be solid glass that ashes are encased in or hollow beads filled with ashes or other items (pet whiskers, hair, bits of cloth, etc) before being made into a pendant. Prices vary depending on size, glass used, etc. Normally custom orders.
Memorial pendants made for a friend. 
Memorial hollow with my cat’s hair. 
Hollow pendants containing pet whiskers and teeth. 
Memorial with pet ashes encased in the glass. 
Memorial with pet ashes encased in the glass. 
Hollow pendant with my cat’s hair. 
Pendant containing organic material (bits of bark and dried leaves) from the tree my husband and I were married under.