What item do I need for the Medium Stable?

[Chi]

Im trying to build the Medium Stable but theres an item I need and I cant tell what it is or where I might find it. Looks like some sort of stone? Its the middle item on the materials list.

And once I get a Medium Stable, will that let me have more than one horse?

[razortail]

You're probably missing Sandstone which is located in the Azurine Valley and Canyon

[Nigolasy]

And you will need pastures and fields to have more than one horse. Your first stable can hold 3 horses if you have one pasture and one field