What Kat says
There are people who believe that certain stones and crystals have certain energies that we can use to help us achieve our goals,heal,and help us.Different stones release different energies and so on.The blue stone looks like an agate of some sort,the pink looks like pink quartz,and the yellow looks like citrine.I could be wrong though.
I wouldn't order them...but,if I were to use stones...I'd go to a local shop and ask questions.My son loves rocks,stones and crystals,so we've gone into some stores that have stones and lists of what they are suposed to help with..he has some citrine and I found a huge chunk of rose quartz in my sister's yard that I kept for decor.