Diamond spade, looks like diamond pickaxe

If you get both the diamond spade and pickaxe in your hotbar when you click on the spade and it is 'in your hand' you see it as a pickaxe. To show this simply click between a diamond spade and then a diamond pick in your hotbar, and the item in your hand remains looking like a diamond pick.

This doesnt apply to the mining qualities of the spade - it still mines gravel quicker than a pick (as normal) it just looks the same.