There is alot of terminology that gets thrown around in this hobby and it can make for a steep learning curve for those fresh to the scene.

The only real difference you should be looking for in live rock is how porous it is.

Color may be an issue as well, but i will not take long for even the greyest rocks to color up once set in a well lit tank.

U can go buy a product called purple ip. Make purple coraline grow like mad. Or I find Kalk topup works well too.