Help with ores (1.7.10)

[neol]

Hello, I am new to minecraft modding.

 

I wanted to ask about ores.

I want to create an ore, that you can only destroy with a stone pickaxe.

But, how do I do that? Do I have to use .setHardness? I set it to 10, which is 3 times the hardness of diamond and I could still break it with the wooden pickaxe.

 

Help, would be nice.

[neol]

Thank you very much.