I've acquired some beautiful looking dizis made from the horns of some animal, which I am quite sure died from natural causes before putting their horns to musical use.
The thing about dizis made from horn is that the horns need to be of a certain thickness before they can be fashioned into dizis. So they are considered rather rare. The dizi is made by joining a few pieces of horn together.
The first type is one made from black buffalo horn. These are more readily available because there are more of them around.
The second type is made from flower ox horn, which is rarely available. They look absolutely gorgeous.
Currently I have a set of 5 (C, D, E, F and G) already reserved by someone.
These type of dizi might not sound as good as those made from bamboo but they are still very much playable. The dizis are made by Xie Bin from Hangzhou.