You can check the enchantment page to see what materials you will need to complete the enchantment you want: http://divinity.wikia.com/wiki/Radcliff#Jewelry_Enchantments

Other materials for less enchantments can be sold. I used to hoard the materials myself but found that they only serve to take up valuable storage space. Once you reach the battle tower the materials become irrelevant since you can send other servants to gather them for you.

The only material in limited supply is Malachite gem (not ore), never sell them! Always buy them when you have an opportunity. They are required for all level 10 (best) enchantments.

There is also a list for potions if you desire to make them instead of purchasing them: http://divinity.wikia.com/wiki/Alchemist