These and the other signature crystals are purchased with guild points from your guild. They cost 500 gil for the dark and light versions and 200 gil for everything else.

You have to sign up to take part. After you do this you have to craft the suggested items during the suggested time to get guild points.

You can only do this for ONE guild. If you change your mind and switch to another guild point system you will lose any points you have at the other guild and will start over. It's kind of like moving towns and conquest points.

Later on in your crafting you will have access to crafting equipment that helps you craft more successfully.