Padparadscha

"Padparadscha" is a pinkish-orange to orangy-pink coloured corundum, with a low to medium saturation and light tone, originally being mined in Sri Lanka, but also found in deposits in Vietnam and Africa. Padparadscha sapphires are very rare, and highly valued for their subtle blend of soft pink and orange hues. The name derives from the Sinhalese word for lotus blossom. Along with rubies they are the only corundums to be given their own name instead of being called a particular colored sapphire.

Fabrication

Because of its rarity, padparadscha is frequently fabricated via synthetics in laboratory settings, or on regular pink or orange sapphires by a process of beryllium surface diffusion. This diffusion process involves heating the stone along with crushed chrysoberyl, the source of the beryllium in the treatment.

The vast majority of padparadscha sapphires (and most other colors of sapphire) are heated in varying temperatures to enrich color and improve clarity. While this may have a negative effect on the price of the stone, it is an accepted practice so long as it is disclosed to the buyer in the process of the sale.

Treating stones with surface diffusion, however, is generally frowned upon; as stones chip or are repolished/refaceted the 'padparadscha' coloured layer can be removed. (There are some diffusion treated stones in which the color goes much deeper than the surface, however.) The problem lies in the fact that treated padparadschas are at times very difficult to detect, and they are the reason that getting a certificate from a reputable gemological lab (e.g. Gubelin, SSEF, AGTA, etc.) is recommended before investing in a padparadscha.

The rarest of all padparadschas is the totally natural variety, with no beryllium or other treatment, and no heating. To find a stone that is certified by a reputable lab as being completely natural is extremely rare and the stone will be very expensive. High quality, unheated and untreated natural padparadscha sapphires will start off in the range of $5,000 per carat and rise by size, color, tone, cut, and clarity, to $20,000–30,000 per carat.

Properties

*Composition: Al₂O₃
*Mohs hardness: 9
*Specific gravity: 4.00.
*Refractive index: 1.762–1.770.
*Crystal system: Hexagonal (trigonal)
*Colors: Mixture of pink and orange
*Pleochroism: Weakly dichroic: two shades of the body color
*Phenomena: None
*Treatments: Often heated; surface diffusion

References

Hall, Cally (1994). Gem Stones. DK Publishing. ISBN 1-56458-498-4

ee also

*Corundum
*Ruby
*Sapphire
*Gemstone