I had the same thing happen to me, actually 3 round butter stains on a brand new counter top at a friend's house! Panic city! Thanks to all your info i was able to remove them. I tried the baking soda but that didn't help much... I tried salt as well... what worked the best for me was to pour boiling water on the stains, wipe it out and repeat the process till the stone was warm, then I poured Energine Spot Remover and let it soak in. I had seen that plaster poultice were a good way to remove the stains as well but didn't have any so after the Energine was absorbed I put a tick layer of clay (which i had) over the stains and let it dry (you can scrape the clay when it's dried and re-use it buy mixing it with water as you will have to repeat this several time) I had to repeat the process about 4 or 5 times but it's all gone now! Thank God! And thanks to all you guys! :-)