In today’s jewellery market, the naming of many stones as “Padparadscha” is problematic — or, to put it more mildly, does not comply with the internationally accepted grading standards for Padparadscha sapphires.
Mainstream international gemmological laboratories generally follow LMHC Information Sheet #4 when identifying and naming Padparadscha sapphire, in order to address the long-standing confusion surrounding this terminology in the global gemstone trade.
According to the LMHC definition:
“Padparadscha sapphire is a variety of corundum from any geographical origin whose overall colour appearance is a subtle mixture of pinkish orange to orangey pink with pastel tones and low to medium saturation when viewed in standard daylight — in the range between D50, 5000 K and D65, 6500 K — preferably with a Colour Rendering Index, or CRI, of 95 or higher.”
The LMHC also clearly specifies the circumstances under which a corundum should not be identified as Padparadscha.
1. if the stone has any colour modifier other than pink or orange, even when induced by scattering effects from tiny inclusions, or turbidity.
For example, in the report shown below, this pink-orange sapphire displays a distinct purplish tone. Therefore, it can only be identified as Purplish Pink Sapphire, rather than Padparadscha.
2. if the stone shows major uneven colour distribution when viewed with the unaided eye, table-up, within a range of plus or minus 30 degrees.
This means that when the stone is observed face-up with the naked eye, its colour appearance should be sufficiently even. If there is obvious uneven colour distribution, it should not be named Padparadscha.
3. if yellow or orange epigenetic material is present in fissures and affects the overall colour of the stone.
As shown in the image below, the right side of the gemstone represents its true body colour, while the orange colour on the left side is the result of interference from foreign material.
In other words, the orange component of a Padparadscha sapphire must come from the corundum itself, rather than from external orange or yellow substances present in fissures.
4. if the colour of the stone is not stable and shifts out of the Padparadscha colour range, for example shifting to pink, as determined by a colour stability test.
Colour stability is one of the mandatory requirements for identifying a sapphire as Padparadscha. If a stone’s colour changes significantly under testing and no longer remains within the Padparadscha colour range, it should not receive the Padparadscha designation.
5. if the stone has been treated by irradiation, lattice diffusion of foreign elements other than hydrogen, or if it contains glass-filled fissures and cavities, with or in combination with glass as a manufactured product.
Such treatments go beyond what is acceptable for a stone to be identified as Padparadscha under the LMHC guidelines.
6. if the stone has been dyed, coated, painted, varnished, or sputtered.
These forms of artificial surface or colour treatment also disqualify a stone from being named Padparadscha.
In other words, for a pink-orange sapphire to be identified as Padparadscha, it must meet all of the following criteria:
1. It must not show any colour modifier other than pink and orange. In an ALGT report, the colour description should only include Pink and Orange.
2. It must not contain orange or yellow inclusions that affect the overall colour. In an ALGT report, there should be no comment such as “Orange color is due to the orange inclusions.”
3. It must pass the colour stability test and show no visible fading. In an ALGT report, this may be stated as: “The ALGT fade test was performed and showed no visible fading.”
4. It must not have undergone treatments such as lattice diffusion, filling, irradiation, coating, dyeing, or any other treatment beyond accepted pre-treatment conditions.
Mainstream international gemmological laboratories generally follow LMHC Information Sheet #4 when identifying and naming Padparadscha sapphire, in order to address the long-standing confusion surrounding this terminology in the global gemstone trade.
According to the LMHC definition:
“Padparadscha sapphire is a variety of corundum from any geographical origin whose overall colour appearance is a subtle mixture of pinkish orange to orangey pink with pastel tones and low to medium saturation when viewed in standard daylight — in the range between D50, 5000 K and D65, 6500 K — preferably with a Colour Rendering Index, or CRI, of 95 or higher.”
The LMHC also clearly specifies the circumstances under which a corundum should not be identified as Padparadscha.
1. if the stone has any colour modifier other than pink or orange, even when induced by scattering effects from tiny inclusions, or turbidity.
For example, in the report shown below, this pink-orange sapphire displays a distinct purplish tone. Therefore, it can only be identified as Purplish Pink Sapphire, rather than Padparadscha.
2. if the stone shows major uneven colour distribution when viewed with the unaided eye, table-up, within a range of plus or minus 30 degrees.
This means that when the stone is observed face-up with the naked eye, its colour appearance should be sufficiently even. If there is obvious uneven colour distribution, it should not be named Padparadscha.
3. if yellow or orange epigenetic material is present in fissures and affects the overall colour of the stone.
As shown in the image below, the right side of the gemstone represents its true body colour, while the orange colour on the left side is the result of interference from foreign material.
In other words, the orange component of a Padparadscha sapphire must come from the corundum itself, rather than from external orange or yellow substances present in fissures.
4. if the colour of the stone is not stable and shifts out of the Padparadscha colour range, for example shifting to pink, as determined by a colour stability test.
Colour stability is one of the mandatory requirements for identifying a sapphire as Padparadscha. If a stone’s colour changes significantly under testing and no longer remains within the Padparadscha colour range, it should not receive the Padparadscha designation.
5. if the stone has been treated by irradiation, lattice diffusion of foreign elements other than hydrogen, or if it contains glass-filled fissures and cavities, with or in combination with glass as a manufactured product.
Such treatments go beyond what is acceptable for a stone to be identified as Padparadscha under the LMHC guidelines.
6. if the stone has been dyed, coated, painted, varnished, or sputtered.
These forms of artificial surface or colour treatment also disqualify a stone from being named Padparadscha.
In other words, for a pink-orange sapphire to be identified as Padparadscha, it must meet all of the following criteria:
1. It must not show any colour modifier other than pink and orange. In an ALGT report, the colour description should only include Pink and Orange.
2. It must not contain orange or yellow inclusions that affect the overall colour. In an ALGT report, there should be no comment such as “Orange color is due to the orange inclusions.”
3. It must pass the colour stability test and show no visible fading. In an ALGT report, this may be stated as: “The ALGT fade test was performed and showed no visible fading.”
4. It must not have undergone treatments such as lattice diffusion, filling, irradiation, coating, dyeing, or any other treatment beyond accepted pre-treatment conditions.
Gallery
Click any image to enlarge
