The simplest points to remember in buying gemstones is that diamonds are the most durable or strongest followed by sapphires. If you buy star sapphires, the durability diminishes since the star shape is actually a deformity in the sapphire stone. The same is true of diamonds. When seen under the glass of the jeweler’s, one can see cracks, lines, and other signs of imperfections which makes the diamond less durable. Those diamonds with visible imperfections are less expensive than diamonds that have no visible imperfections to the naked eye or to the jeweler’s glass. Another aspect to consider when buying gemstones is rarity. A gemstone is more valuable when there are fewer of them around. When the market becomes glutted with diamonds, their value goes down. Gemstones like rubies are more expensive than garnets although both are red stones. The reason is that rubies are rarer, more durable, equal to the diamond and to the sapphire and many are considered to be the most beautiful stones in the world because of their color. The question of beauty in gemstones depends on individual tastes. However, in general, the gemologist would say that the ruby is the most beautiful stone and therefore more valuable than even many diamonds, sapphires and emeralds, that are also beautiful, rare and durable.