@Terence Cheesman Nice find! I like this coin lovely toning and nice sharp portrait. I wish I had this mine is good too but I am always worried it breaks since internally crystallized.
I don't know what to say about your coin with the crystallization. If you really like try to protect it as much as possible. If the problem starts to "devour the coin" then all I can say is to try to sell the coin and use the money to buy something else that will make you happy. My first denarius of Tiberius was really nasty. It was less than VF with scratches and some pitting. It did its job until I found a better coin which eventually did lead to this one.