Colored Stones & Pearls 归档

GIA Holiday Shopping Guide: How to Buy Pearls 101

December 11, 2014

Captivated by pearls? You’re certainly in good company. A favorite of legendary women including Cleopatra and Queen Elizabeth, these beautiful spheres are the only precious gems made from a living creature – the mollusk. (more…)

Tanzanite Buying Guide

December 1, 2014

Notable for its majestic blue velvet and intense royal purples, the first of December’s birthstones is named after the only country it can be found: Tanzania. Exceptional tanzanite can display three distinct colors in three crystal directions. (more…)

Rock Candy – Fantasy Cut Gemstones

November 17, 2014

There’s magic and fantasy in gemstones, and a group of cutters are master conjurers. (more…)

The Magic of the Fantasy Cut Gemstones

November 13, 2014

Fantasy cut gemstones exhibit so many unique optical characteristics that they often appear to live up to ancient lore – that gems are imbued with magical properties.

So called fantasy cut gemstones often owe their spectacular beauty to unique faceting artistry that is achieved through cutting non-traditional design elements. These techniques cause light to reflect and refract differently, surging into view as stunning displays of light and color along the gems’ surface and interior. (more…)

Citrine Buying Guide

November 11, 2014

Perhaps the most popular and frequently purchased yellow gemstone, citrine is a variety of quartz, and a November birthstone. While it’s an attractive alternative for topaz as well as yellow sapphire, natural citrine is actually quite rare, and those without color zoning or visible inclusions are highly sought after. (more…)

Topaz Buying Guide

November 1, 2014

One of November’s birthstones, topaz has the unique ability to show different colors in different crystal directions. Ancient civilizations believed that topaz gave them strength, long life, beauty, and intelligence. (more…)

Jinxed Gems

October 27, 2014

Everyone loves a good Halloween scare, so we scoured the gemological literature for stories about cursed gemstones. Here are a few tales we dug up about these bone-chilling beauties. (more…)

Tourmaline Buying Guide

October 18, 2014

Featuring one of the widest color ranges of any gem, tourmaline is one of October’s two birthstones. A favorite of mineral collectors everywhere, tourmalines come in all shapes, sizes, color saturations and tones – from expensive electric blues to affordable olive greens.

(more…)

The Van Pelts and the Art of Gem Photography

October 9, 2014

Gems & Gemology (G&G), GIA’s award-winning peer-reviewed journal, is celebrating 80 years of publication, 1934-2014. The venerable journal has long been respected for sharing invaluable information with gem and jewelry professionals – and for its breathtaking photography. (more…)

Opal Buying Guide

October 1, 2014

October’s birthstone, Opal, displays a unique play-of-color that some say looks like fireworks, lighting, or galaxies trapped inside the stone. The patterns and colors that result from the stone’s interaction with light make each opal one of a kind. (more…)

Captivated by Coral

September 25, 2014

We’ve been wearing coral jewelry for at least 30,000 years – an impressive testament to its timeless appeal.

Coral comes in an array of colors: white, cream, various shades of red and orange, blue, a light grayish violet called “lavender” in the trade, and a light, vivid pink color sometimes referred to as “angel’s skin”. There is also black and golden coral. Red coral (sometimes called “ox blood” in the trade) has historically been the most expensive. Gem-quality coral has uniform color. (more…)

The Big Deal about Little Inclusions

September 9, 2014

Clarity characteristics on a gemstone’s surface are called blemishes. Inside the stone, they are referred to as inclusions.. This post will focus on inclusions and how they are important factors to gem and jewelry professionals and consumers.

Inclusions can be very small, but they mean a lot. In general, the fewer inclusions, the greater the desirability. (more…)

GIA 4Cs Diamond Blog