The International Gemological Institute will help launch the Tanzanite Foundation’s tanzanite grading report, two years after the foundation introduced its quality-grading scale. The Tanzanite Foundation was created by TanzaniteOne, the mining company responsible for the largest portion of the Merelani Hills tanzanite deposit in Tanzania.

The report includes the traditional “four Cs” but grades colors using one of two color-grading scales. The first scale is bluish-violet (more violet than blue); the second is violetish-blue (more blue than violet). Both scales are divided into six saturations, ranging from exceptional to pale.

The clarity scale consists of four grade ranges, from eye clean to heavily included. Cut is graded in four categories, from excellent to fair.

Tanzanite grading reports issued by IGI also will provide country-of-origin authentication. At present, tanzanite is commercially available only from Tanzania, but documentation will become important if another tanzanite locality is ever discovered.

IGI will offer the Tanzanite Foundation certificate to the foundation’s members. According to the foundation, “These certificates provide the additional assurance that members operate in accordance with strict ethical standards upholding best-practice principles.” Members can have stones laser-inscribed with the foundation’s logo, the Mark of Rarity, as well as the certificate identification number. The foundation says the logo is its guarantee of “quality, rarity, and distinction.”

Following the De Beers model, TanzaniteOne offers “sights” to eight distributors, which supply a large percentage of the world’s tanzanite to gemstone houses and jewelry manufacturers. It expects the quality-grading scale to make distribution and pricing of sights more consistent, boost the value of higher-quality tanzanite, and decrease the value of lower-quality goods.

IGI will launch its grading system with the Tanzanite Foundation’s Celebration of Life Jewelry Design Awards collection. The 21 winning pieces were showcased at the New York Public Library in January.

The Tanzanite Foundation says a portion of the proceeds of all tanzanite purchased by foundation members from producer members is channeled back to local communities in Tanzania.