Jewelry retailers need to know what colors are in fashion and how they complement other colors. They need to understand which gems look good in daylight (cool colors) and in the evening (warm colors).

Be the gemstone authority in your town. Instead of asking customers their birth month, ask: “What colors look good on you?”

The most popular gems at last October’s Intergem Exhibition in Idar-Oberstein, Germany, weren’t emeralds, rubies, and sapphires. The gems drawing the most attention were ambers and agates, chalcedonies and jaspers, hauyne and coral, rock crystal quartz, smoky quartz, citrines, amethysts, rutilated and tourmalinated quartzes, druses, and a host of other gem materials.

Next time someone asks about buying a piece of gem-set jewelry, try pulling some of the following out of the showcase.

For evening wear, suggest kunzite from Afghanistan, or morganite from Brazil. Some of these lighter pink gems tend to fade over time under continuous strong lighting environments (like your showcases or the beach), so disclose that information and offer these gems for nighttime use.

Organics include various shades of pink coral and shell along with pink pearls, a natural light color in many of the freshwater varieties, as well as a darker pink found in conch pearls from the Caribbean. You also can offer dyed Chinese freshwater cultured pearls as a bold and inexpensive pink fashion statement. (Note: Organic gem materials such as corals and ivories need to be fully researched with your suppliers so you don’t contribute to endangering the environment or the species themselves.)

For budget-conscious lovers of pink, offer translucent-to-opaque gem materials such as Peruvian pink opal, Brazilian rose quartz, or Venezuelan rhodochrosite. You’ll most likely find these in cabochons or tiles. Rose quartz is durable (7 in hardness), but the softer rhodochrosite (4) and opal (6) should be reserved for occasional outings. These gems can be accented by tanzanites, diamonds, or sapphires to enhance the value of a piece.

For the budget oblivious, there are pink diamonds. The lighter shades of pure pink tend to come from southern Africa, while the darker, more saturated purplish pinks tend to come from Australia (Argyle) and alluvial deposits in South America.

This category also offers phenomenal properties: pink star sapphire (pricey), pink cat’s-eye tourmaline (affordable), and star rose quartz (very affordable).

Red. Rubies from Africa and Afghanistan represent red’s high end. (Treatments are a concern because highly fractured rough corundum is being filled with yellow/golden colored glass, enhancing its transparency, color, and stability.) Rubies are routinely heat-treated to enhance their color.

Mid-range reds include spinels from Africa and Burma, tourmalines from Brazil (some natural color, some possibly irradiated), and the rare red beryl from Utah (marketed as “red emerald.”) There are reddish sunstones from Oregon, with and without schiller.

At the very affordable end of the spectrum, offer garnets such as almandite or pyrope. In the opaque category, try red jaspers or dyed red agates.

Be careful purchasing red coral, since past fishing procedures are not necessarily accepted as environmentally appropriate.

Sunset (reddish-orange). Traditional padparadscha, a natural-color (no heat treatment), medium-light, saturated pink-orange sapphire, is from Sri Lanka. East Africa produces pink-orange sapphires with heat-enhanced color, as well as darker, more saturated natural-color stones. There are also beryllium-treated pink-orange sapphires. These treatments and color variations greatly affect value, but will have little or no effect on personal taste.

Gems with darker, more saturated hues include spessartite and hessonite garnets and spinels, citrine quartzes, and Mexican and Brazilian fire opals. Morganite falls into the subtle pink-orange “peach color” range.

As for imperial topaz, sunset is the only color—not just any yellow.

Orange. Sapphires, of course, come in a rainbow of colors, natural as well as treated, including orange. Orange garnets include hessonites and spessartites, and quartzes include citrines and translucent carnelian chalcedonies. Fire opals from Mexico and Brazil also fall into this color category.

Yellow. Yellows include diamonds, sapphires, topazes, tourmalines (including the canary yellows from Africa), chrysoberyl (very wearable), golden beryls, citrines, feldspars, and even brazilianites.

In the translucent to opaque yellow, try offering a Peruvian opal or tigers-eye quartz. Pearls range from creamy to golden.

Olive. Peridot is the birthstone for August and is the classic olive stone. Usually faceted, it’s an acquired taste. But get a gem carver or gem artist to attempt something more unusual, add a few accent stones, and you’ll create some converts.

Many natural demantoid garnets are yellowish-green, but demantoids these days can be heated to drive out the yellow component. You also can find olive-color tourmalines, prehnites, chrysoberyls, spodumenes, and ambers.

Green. Emerald is the best-known choice. Birthstone for May, emerald is often thought too fragile for anything but evening wear. But emerald has a hardness of 7.5, so it can be worn without easily scratching. As for its toughness—resistance to breaking—if you have an emerald with a few fissures, depending on the location of those fissures, the stone should be able to withstand everyday wear. Most fissured emeralds will be filled with oils, resins, or epoxies. Marketing for the branded filler Excel guarantees its quality and claims that emeralds filled with Excel can be cleaned using an ultrasonic or steam cleaner. Alternatives include tsavorite garnet, chrome tourmaline, and chrome diopside.

Demantoid garnet is good for an “estate” look, and translucent grossularite garnet or any of the jades provide a softer oriental touch. Chrysoberyl, zoisite (marketed as “green tanzanite”), fluorite, and the banded look of malachite give you even more options.

Sky blue. Brazilian (irradiated) blue topaz is a natural for this category, along with cuprian tourmalines from Paraíba, Brazil; Mozambique; and Nigeria. Apatites make a fine substitute for cuprian tourmaline.

Blue zircons are affordable options, and in the translucent-to-opaque selections, turquoise is a natural. (But note that turquoise treatments abound.) Try offering Peruvian blue opal or blue crazy lace agate. You can also find turquoise, blue moonstone, and Australian blue opal with play-of-color in cabochons or in carved designs.

Dark blue. (royal and navy). Tanzanite has been so popular over the past few years that you most likely have some in inventory already. It’s the birthstone for December, but its color complements year-round fashion. Iolite and kyanite come to mind for uncommon substitutes, with lapis the obvious choice for cabochons and carvings.

Purple. Say “purple” and people respond “amethyst.” But tanzanite also can fit nicely. As for more unusual gems, stock a few spinels, some rhodolite garnets, some fluorite, sugelite, and charoite, just to be different.

Black. If you’re familiar with estate pieces containing jet, you’ll be glad to know jet is available, and in good quality for fine jewelry. Black diamond is available in a range of qualities and price ranges, depending on clarity and how the color was created (natural, heat treatment, or irradiation). Most natural blacks will be highly included, while heat-treated blacks will be opaque. Irradiated black diamonds (actually a very dark green) are commonly of gem clarity.

You’ll find faceted black spinels, along with beads, at most of the major gem shows. They make terrific accents to any major colored gem.

Black chalcedony, aka black onyx, has been available for so long that most have forgotten the material is dyed black. True black onyx will have a white strip of chalcedony running through it, which makes the perfect gem material for cameos.