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Bismuth is rarely found naturally in its elemental form (even less commonly than platinum), but lab-grown crystals are gaining in popularity for their unique geometric formations (hopper crystals) and phenomenal iridescence. Bismuth is a silver-white metal, but an oxide layer forms immediately when crystals make contact with air. This produces an array of colors similar to that of a soap bubble or oil on water. The different colors are dependent upon the thickness of the oxide layer, which determines how light is reflected off of the surface creating a striking rainbow effect.

Apophyllite is divided into three distinct species, fluorapophyllite, hydroxyapophyllite and natroapophyllite, depending on their chemical composition. It was once considered to be a single mineral, so if chemical composition is not yet determined specimens will still be referred to as apophyllite. It is commonly found as glassy prismatic, blocky, or tabular white to grayish or light pastel crystals. The name apophyllite comes from the Greek word meaning "leafs off," referring to its tendency to flake when heated.

Indicolite is one of the most valuable and collectible of all elbaite tourmalines, with hues spanning from lighter to deep, intense blues. Cutting indicolite can be a task for even the most skilled of cutters, as it is strongly pleochroic and appears darker when viewed down the crystal. This factor must be taken into consideration when cutting, as a loss of transparency and brilliance can occur in darker specimens.

Displaying characteristic yellow to orangish yellow and greenish yellow, heliodor is the most cheerful variety of beryl. Interestingly, as an allochromatic gem, pure beryl is colorless, with traces of different elements responsible for beryl's wide range of colors. Heliodor is named from ancient Greek words meaning "gift from the sun," as it was once believed that heliodor harnessed the power and warmth of the sun and was responsible for the change between day and night.

The chemical vapor deposition (CVD) process deposits a thin film onto part of the surface of a colorless quartz gemstone. This creates an eye-catching rainbow effect as light passes through the gem, resulting in an unbelievable array of colors.

Henry Platt, former president of Tiffany & Co., described tanzanite's discovery in 1967 as the most important gemstone find in 2000 years! A single 5-mile strip of land in Tanzania remains the only commercially viable source of this stone that has become one of the world's most sought-after and admired gems. Tanzanite is a relatively new gemstone in the world of gemology and jewelry. Though its history is brief, it is no less illustrious than many ancient gems. Tanzanite is a single-source gemstone that is a thousand times rarer than diamond, and it is only gaining popularity.

Highly coveted South Sea pearls are often described as the pinnacle of cultured pearls--they're certainly among the most rare and expensive available. Primarily farmed in the pristine waters off Australia, the Philippines, and Indonesia, South Sea pearls are generally much larger than other pearl types, ranging from nine to 20 millimeters, and have a unique luster due to their nacre coating. As there are two varieties of this oyster, a gold-lipped and silver-lipped, pearls can be both white to silver and golden.

Selenite is the name for transparent, colorless to near colorless crystals of gypsum, a hydrous calcium sulfate that is found in a number of forms. The name "selenite" comes from the Greek word selene, meaning "moon", no doubt in reference to the gem's white glow. Gypsum, in all varieties, is very soft and has perfect cleavage so it should be handled with care.

Although freshwater pearl cultivation originated in Japan, China is now the world's major producer of freshwater pearls. The humble freshwater mussel, while not as widely celebrated as its cousin the oyster, is capable of producing high-quality pearls. Generally speaking, freshwater pearls do not have the luster and shine of saltwater pearls, but they do form in a variety of shapes and colors and are typically sold at lower prices.

Enstatite is a common silicate mineral in the pyroxene family. Enstatite’s normal color range includes shades of green to brownish green, yellow green, yellow to brown, orange to reddish brown, and colorless. This gem has been identified in meteorites, and it is believed to be one of the early stages of crystalline silicate formation in space.

Named after the country, Afghanistan, where it was first discovered in a lapis lazuli mine in 1968, this rare and complex aluminosilicate forms blue crystals ranging from light aquamarine shades to saturated sapphire blue hues. The scarcity of gem-quality afghanite makes it a true collector's stone.

Not well known to the general public, howlite is one of those minerals that is almost more famous for imitating turquoise. Howlite is naturally milky white in color and often has dark vein-like mineral inclusions. Because of its porosity, it accepts dye fairly easily, achieving a turquoise-like blue color. Howlite accepts a nice polish and its porcelain-like luster is appealing.