Gemstones from G to O
A colorful, brief background on the major gemstones used in jewelry today. Each gem includes a description, a photo of the crystal, and then cut gems. In this issue we are featuring Garnet and to Opal, and the many gems in-between!
Garnets are a set of closely related minerals that form a group, resulting in gemstones in almost every color. Colors range from fiery red pyrope and vibrant orange spessartine to rare, intense-green varieties of grossular and andradite.
Known in the jewelry trade as iolite, this mineral is called cordierite by geologists and mineralogists. It was named after French mineralogist Pierre Cordier. Incorrectly called “water sapphire,” it can display a blue to violet hue in one direction and pale yellow to colorless in another. According to legend, Vikings used iolite slices to reduce glare when checking the sun’s position.
Jade is actually two separate gems: nephrite and jadeite. It comes in the well-known green colors, as well as yellow, reddish orange, white, gray, black, brown, and lavender. Prized by civilizations from ancient China to the Aztecs and Mayans of Central America, jade is crafted into objects of stunning artistry. In China, a pierced jade disk is a symbol of heaven.
Collectors love kunzite for its color range, from delicate pastel pink to intense violet-purple. Trace amounts of manganese give this pink to violet variety of spodumene its feminine glow. A relative newcomer to the gemstone stage, Kunzite was only confirmed as a unique variety of spodumene in the early part of the twentieth century.
Lapis is a stunning rock, an aggregate of several minerals, mainly lazurite, calcite, and pyrite. Lapis lazuli is treasured for its beautiful deep blue color. Afghanistan is considered the source of the best-quality lapis.
A ghostly sheen moves under the surface of this feldspar, like moonlight glowing in water, hence the name. Feldspar is prized for its billowy blue adularescence, caused by light scattering from an intergrowth of microscopic, alternating layers. Moonstone is a favored gem of many Art Nouveau jewelry designers.
Morganite is the pink to orange-pink variety of beryl, a mineral that includes emerald and aquamarine. This gem gets its subtle blush when a trace amount of manganese makes its way into the delicate crystal structure.
Fireworks, jellyfish, galaxies, lightning — Opal’s shifting play of kaleidoscopic colors is unlike any other gem. Its microscopic arrays of stacked silica spheres diffract light into a blaze of flashing colors. An opal’s color range and pattern help determine its value.
There you have this month’s gems from Garnet to Opal! Watch for a new set coming next month!
Photos and info courtesy of GIA.com.