Blender - Item duplicated, items are linked?

I duplicated a mesh that I had modeled. I went to put a texture on the duplicated object, and it changes the original. I want to have separate textures for each. Any changes I make for one go to the other. Help?

 

Select the duplicated object in the scene. Go to the GameObject menu and select 'break prefab instance'. Now the duplicate is not linked to the original.

And/or:

You may still be using the same material for both instances. Select a different material in the duplicates mesh renderer. Create a new material if necessary and then change the textures on this other material.

This is assuming you duplicated the mesh in the scene, rather than in the project.

 

..... I'm using Blender?

 

Sorry, I thought you were talking about an asset in Unity that you had created in blender, didn't realise you were talking about work in blender itself.

 

To fix the duplicates you have, select one of them and make it a single user copy (see attached screenshot).
Just use shift-d to duplicate instead of alt-d from now on. (alt-d creates a duplicate of the model sharing the same mesh data)