One of the main advantages of buying gems online is that the expense can be incredibly reduced than buying it directly from the store. Most of the gem stores online offer lower overhead costs and thus the savings would reach the customers. Another advantage is that you don't have to waste your time and money traveling from one store to another. Every gem production would be only a few pressure of your mouth.
Above all, the precious gemstones that you purchase should be worth the money. The precious gemstone is expected to last for a life time and sometimes they may be carried down the generations even. So the quality of the gems is essentially important.