Mixing grow Mediums

Hey guys i am really excited because i almost got all of my parts for my first time grow.

There is one question at the moment that i want to ask for some advice.

Can i put 1.5 inch rock wool and transplant my seedlings to 3x3 Grodan Gro-Blocks. are they the same thing or different. will it ruin, kill, or deformed my crops. because i did lots of online shopping trying to find the best deals. And i didn't' do a 100% check on my shopping list.

thanks in advance