Blue sapphire from Maydan Shahr, Afghanistan. The Summer 2002 Gem News International section (p. 181) documented dark blue sapphires from a new deposit in Afghanistan, which was represented as “Medan Khar” in Vardak Province, west of Kabul. Since that time, this province has been the source of additional sapphires, reportedly from the Maydan Shahr area. It is not clear if this new production is from the same locality (with phonetic allowances for the different spellings) or a different deposit. The sapphires are enclosed by a hard white matrix, which makes their recovery quite labor intensive. Mr. Hashmi saw several kilograms of rough in Peshawar, and most had a hazy or velvety appearance, as well as a slightly grayish tinge, which differed from the Afghan sapphire we reported on in 2002.

An examination of the 2.10 ct oval mixed-cut sapphire in figure 1 by one of us (EPQ) showed the following properties: color—dark grayish greenish blue, with medium bluish green and dark violetish blue dichroism; diaphaneity—transparent; R.I.—1.761–1.770; birefringence—0.009; S.G.—4.03; fluorescence—inert to both long- and short-wave UV radiation; and strong absorption bands at 450, 460, and 470 nm visible with the desk-model spectroscope. This stone displayed a medium to strong blue scattering effect when viewed with a fiber-optic light. This effect was caused by the reflection of light off clouds of very fine particles throughout the stone, resulting in a somewhat hazy appearance. Microscopic examination revealed a “fingerprint,” a twin plane, a transparent near-colorless birefringent crystal, stringers of pinpoints, and diffuse planar yellow and blue growth banding. No evidence of heat treatment was detected.

Five Batakundi sapphires (0.74–1.98 ct; see, e.g., figure 2) were examined by one of us (EPQ) and the following properties were recorded: color—purplish pink, pink, and slightly orangy pink, with moderate dichroism in purplish pink to purple-pink and pinkish orange to pink-orange; diaphaneity—transparent to semitransparent; R.I.—n_e=1.759–1.760, n_o=1.767–1.768; birefringence—0.008; S.G.—4.00–4.03; fluorescence—moderate to strong red to long-wave and very weak red to short-wave UV radiation. The desk-model spectroscope showed general absorption to 430 nm, a weak 450 nm band, weak 470 and 480 nm lines, a 550–590 nm band, and lines in the red end of the spectrum.

All but the smallest stone displayed a moderate violet-blue scattering effect when viewed with a fiber-optic light. As with the Afghan sapphire reported above, this effect was caused by reflection of light off clouds of very fine particles throughout the stones, which gave them a hazy appearance. Microscopic examination revealed that all five samples contained “fingerprints,” fractures, dark metallic inclusions, transparent near-colorless birefringent crystals (one of which was identified by Raman analysis as zircon), straight and/or angular growth banding (purplish pink to pink), and short needles resembling rutile. Also present were twin planes in four of the stones, needles (with the appearance of boehmite) and two-phase inclusions in three samples, and an angular blue color zone and large transparent crystals (one of which was identified by Raman analysis as apatite) in the smallest stone. No evidence of heat treatment was detected in any of the sapphires. However, one showed evidence of clarity enhancement (i.e., it “sweated” when tested with a thermal reaction tester).

Purple sapphire from northern Pakistan. Another deposit in northern Pakistan is the source of purple sapphires. Mr. Hashmi was not able to learn the specific locality. He reported seeing less than 1 kg of rough in the Peshawar market.

Elizabeth P. Quinn and Brendan M. Laurs
Gemological Institute of America, Carlsbad