We can break down the price ranges of the different gem varieties into five basic categories: Traditional Gemstones, New Classics, Connoisseur Gems, Collector Gemstones and Affordable Gems.
These categories have basic price ranges. Lower quality stones, or stones with less popular colors, may cost less. Meanwhile, stones with particularly fine quality or color may cost more. These price ranges are meant to give you a general idea of the price relationship between the different varieties of gemstones.
TRADITIONAL GEWMSTONES
These are the ruby, the emerald and the blue sapphire. Because of their lasting appeal and distinguished history, they are usually more valuable than other colored gemstones.
Generally, rubies and emeralds are priced higher than a sapphire of comparable quality, due to rarity. For a one-carat stone of average-to-good quality you can expect to pay between $250 and $10,000 per carat. Of course, truly fine gems will cost more.
NEW CLASSICS
Then there are the gemstones that are the rising stars of the jewelry industry: tanzanite, tourmaline, aquamarine, imperial topaz, and tsavorite garnet. These gemstones are usually available in standardized sizes, but you really should look at some of the fine, larger single stones to see why they have so many fans.
Gems in this category range from $50 to $1,000 per carat, for an average-to-good-quality one-carat stone. As a perfect example, tsavorite easily can reach $3,000 per carat.
CONNISEUR GEMS
These are gemstones that have a more specialized market because they are more of a rarity. They include black opal, jadeite, pink topaz, chrysoberyl cat's-eye, fancy colored sapphires, and rare stones like demantoid garnet and alexandrite, which are practically "extinct" in rough form.
These gemstones are highly prized, with prices that range from $250 to $5,000 per carat. For instance, an alexandrite with a good color change will command at least $10,000, even in a one-carat size.
COLLECTORS ITEMS
These are not available in quantity to be marketed effectively, so you get a lot of beauty for the money. This category includes spinels, zircons, moonstones, morganites and other beryls, along with many other rare gemstones. Red and hot pink spinels can command a few thousand dollars per carat, but most of the gems in this category will sell for hundreds, not thousands, even those specimens with excellent color.
AFFORDABLE GEMS
The more affordable gems combine great color with surprisingly reasonable prices and good availability. These stones include some old favorites, as well as some new ones: amethyst, white opal, citrine, ametrine, peridot, rhodolite garnet, blue topaz, iolite, chrome diopside, kunzite, andalusite, and many ornamental gemstones such as lapis lazuli, turquoise, onyx, chrysoprase, nephrite jade, and amber. Prices for these gemstone range between $5 and $100 per carat for a one-carat stone.
UNDERSTANDING VALUE
In every gem variety, especially the more expensive ones, you should expect to pay more for matched pairs, sets, and special shapes and cuts.
When you shop for gemstones in jewelry stores you will see a range in qualities. Generally, you will find low-to-medium quality gemstones set in jewelry, and a wider range of qualities in unset gemstones. Often, the jeweler will have to call in top-quality gemstones from a supplier: most jewelers do not stock a wide selection of fine gems even in ruby, sapphire and emerald.
How can you comparison-shop on the web? Very carefully. Some sites make extravagant claims about the "investment quality" of their stock. With gemstones, color is the most important value factor; but it's difficult to compare color online, because the differences between monitors make the color comparison of even the best photographs difficult.
To counter this effect, the better gem retailers such as My Jewelz will stock and sell only top-quality gems, because it's very difficult to show subtle differences in quality on the screen. Also, a liberal return policy can assure you of the opportunity to independently appraise your gem in order to verify its quality.
Certainly, lesser-quality and less expensive gems can be sourced out by retailers who offer finding services. However, before you decide to trade down in quality, think instead about choosing a top-quality gemstone in a more unusual gemstone variety.
credit: http://www.myjewelz.com/understandinggems.asp
