Labs Define Padparadscha

Members of the Laboratory Manual Harmonization Committee have standardized the nomenclature they use to describe a padparad-scha sapphire. The seven member laboratories will define padparadscha as “a variety of corundum from any geographical origin whose color is a subtle mixture of pinkish orange to orangey pink with pastel tones and low to medium saturations.” LMHC comprises the American Gem Trade Association’s Gemological Testing Center (United States), CISGEM (Italy), GAAJ Laboratory (Japan), GIA Gem Laboratory (United States), GIT Gem Testing Laboratory (Thailand), Gübelin Gem Lab (Switzerland), and SSEF Swiss Gemmological Institute (Switzerland).

There are two important items to note: First, stones don’t have to come from Sri Lanka, which is where the name originates; second, the color must be a light to medium pastel tone with light to medium saturation. That excludes the darker and more saturated African material once promoted as padparadscha, which might be a major blow to those who have purchased material in hopes of getting a padparadscha designation from the labs.

The LMHC definition of what padparadscha cannot be includes the following:

  1. Any stone with a color modifier other than pink or orange, which rules out brown or red stones;

  2. Any stone with major uneven color distribution when viewed with the unaided eye, table up, plus or minus 30 degrees. (This clarification is important, because it allows the classic Sri Lankan–cut stone, which has all the color in the culet. Most of the rest of the stone is virtually colorless, but face up, it looks fine;

  3. Any stone that has yellow or orange color in fissure(s) affecting the overall color of the stone;

  4. Any stone that’s treated. Treatments include lattice diffusion (e.g., beryllium), glass filling, irradiation, dye, coatings, paint, varnish, or sputtering. (Heat is not considered a treatment; it’s an “enhancement.”)

“Introduction of the African material, first Umba, then Tunduru in Tanzania, and then stones from Madagascar, with heat treatment being more refined, and especially with the beryllium treatment, the whole issue of padparadscha had to be redefined,” says Lore Kiefert, director for the AGTA GTC lab. Kiefert notes that laboratories and dealers in the past have not all agreed on what should be called padparad-scha. Among the controversies are whether “pads” can be heated, beryllium treated, or have intense or uneven color.

“LMHC tried to unify all of these new inputs, and seeing that the group consists of laboratory representatives from producing as well as from consuming countries all over the world, the consensus is one that everybody can live with and feels comfortable with,” says Kiefert.

Lab representatives may wait for feedback from their board or their clients before deciding if they can live with the solution.