Quality
Gemstones are unique, and their prices may vary considerably depending on the quality. For example, a ruby can be purchased anywhere from $10 to $1,000,000. In terms of value, it is advisable to purchase a high-quality smaller gemstone than a larger, low-quality one.
Cut and Carat Weight
A gemstone's cut may not always affect its price but can make the overall look of one stone more appealing than another. Looking at similar gemstones will help determine the best cut. The price of a gemstone is more directly based on the carat weight; the larger the stone, the rarer and more expensive it is.
Color and Clarity
A simple rule to follow when choosing a gemstone is to pick one that has a vivid and lustrous shine. Higher quality gemstones have color that is intense and saturated. The clarity of a gemstone is extremely important as well. Clear stones with no visible flaws are the most sought after, and hence the most expensive.