Full disclosure, this is NOT a paid advertisement or sponsorship. However Cover Up did send me the products to shoot and keep. This wasn't in exchange for positive feedback. I like to rep companies that produce products that I love and use. So this is my honest opinion and not a paid plug!
I probably get asked this question every week and at least ten times when I post a picture with it it.
My MacBook doesn't have a case on it, it has 'skin' which is made out of real wood. It has an adhesive back and sticks on the back! It's absolutely awesome, I love it! Although I was an idiot when sticking it on and had to redo it, so the adhesive has worn a bit. However the company that makes them now does skins and cases made out of stone! They look amazing and I think i'm going to have to get my hands on one of those next!
The company that make them are called 'Cover Up'. A UK based company that I started speaking with over Instagram about 6 months ago. Pretty awesome company and pretty awesome products! Go check them out!