Gemscentric

Written by Julian Robov


Forty Three


The blue stones in front of her looked beautiful and brilliant. Carly was learning something different in life. Like people, gemstones too had several natural and deceptive colors and identities beneath their skin—partially due to their geologic and unpredictable growth environments, and the way in which they were identified and described. She was taught how to identify blue sapphires from other look-alike stones. Carly was enjoying the work, as a part-time gemologist—Emily Beryll—from Canada, explained inclusions and treatment with the help of a microscope, books and slides. She was hired by George, who had by now set up a mini-lab in his condominium on Sathorn Road.

Carly was sharp and swift, and her eagle eyes began to recognize the tell-tale signs of identifying blue sapphires—natural verses synthetic verses simulant. In a matter of a few weeks, she began to absorb all the intricate details of gemology with guerrilla concentration and surgical precision—asking questions, and sometimes even correcting Emily. They both were enjoying the challenge. It had been a bit of an investment. He had gone out of his way to do everything he could—to teach Carly gem identification, and once her new American passport with a new identity was ready, she was going to travel with him around the world, buying blue sapphires and other colored gemstones. But first she needed scientific education before making opinions. Otherwise, there was always the possibility of getting gemsicuted (put to death according to a plan because of gemstones) in the gem trade knowing the rough and ignorant landscape.

He bought a new portable lab from America, and in addition to that he bought another set of instruments such as polariscope, dichroscope, spectroscope, microscope, heavy liquids, immersion cell, loupe and tweezers, hydrostatic balance, ultra-violet fluorescence kit, a copy of a photo atlas of inclusions in gemstones and slides. She was thoroughly enjoying the work.

She was given a parcel of blue gemstones by George, who had bought the parcel through an acquaintance in Hong Kong. The parcel was sold as blue sapphires, and since George trusted the source, he didn’t bother to ask any further questions, because he could always return them, in case they were found salted. But he wanted to check them once again, since Carly was becoming proficient in gem identification. Otherwise, he would have sent the stones to an independent gem testing laboratory in Bangkok, before shipping the parcel to New York for sale.

Altogether there were fifty pieces of blue gemstones. After some visual observation she began to study the shape, color, clarity, cut, luster, brilliance and heft. She took five gemstones, and put them in a special tray for individual identification.
She picked up the first blue stone, an oval cut gem. It weighed 4.65carats, and by studying its optic character with a polariscope, it was identified as a double refractive(DR) gem. Dichroscope test confirmed the stone was violet blue to blue green. Then she gently proceeded to the refractometer to measure its refractive index(RI). The reading was 1.762-1.770 with a birefringence of 0.008. She then moved to the microscope to observe inclusions. Several layers of liquid fingerprints, colorless crystals with haloes, two-phase and needle-like inclusions confirmed the stone as natural. Though the spectroscope was difficult to use, she had mastered how to observe the absorption spectrum, and the presence of strong bands at 470 nm, 460 nm, and 450 nm in the blue-green region indicated iron spectrum. With the help of hydrostatic balance she calculated specific gravity(SG). It was 4.02. The luminescence was weak. She then proceeded to observe if it was surface-diffused. With the immersion cell and 3.32 heavy liquid (methylene-iodide), it was quick. The stone was not surface-diffused, because all that she saw was color zoning, not the characteristic color bleeding seen at facet junctions. Her final conclusion: the unknown gem was a natural blue sapphire.

She made note on a worksheet and picked up the remaining four oval cut blue stones. They weighed 3.85carats, 6.50carats, 3.96carats and 8.01carats respectively. The colors were violetish blue face-up (table-up). She went through the same ritual. The results from observation remained consistent. The pieces were natural blue sapphires.
After making notes in a worksheet, she picked up another five stones from the parcel. They weighed 4.95carats, 5.50carats, 6.00carats, 2.98carats and 3.00carats respectively. The colors were a bit lighter, and after testing the optic character with a polariscope, the stones were identified as single refractive (SR). The stones also lacked pleochroism (many colors in different direction) so she decided to check the refractive index (RI) with a refractometer. The readings remained consistent. It was 1.718. Immediately she cleaned the stones with chamois one by one. With the help of a stone holder, she observed their inclusions. They all had octahedral crystals lined a row with needles and two-phase inclusions. The specific gravity (SG) was 3.60. And all the five stones showed similar results. The five unknown gems were later identified as natural spinel.

She selected twenty five blue gems from the parcel and studied their luster, color, brilliance, and shape. They were oval, mixed cut, and to her utter surprise all the twenty five stones weighed exactly 4.65carats each. Something was not right. She began to observe the color and cut again with a loupe. They had been cut like a natural blue sapphire with that usual pavilion bulge and shallow crown. Polariscope results confirmed all the twenty five blue stones as double refractive (DR). A slow but careful refractive index (RI) test with a refractometer arrived at 1.762-1.770 with a consistent birefringence of .008. All the twenty five blue stones had a specific gravity (SG) of 4.00. She then decided to study their inclusions. Curved growth lines and gas bubbles confirmed the stones were all synthetic. Later, she studied all the stones with an immersion cell with 3.32 heavy liquid looking for other tell-tale signs. They weren’t surface-diffused synthetic blue sapphires. She decided to skip fluorescence and spectroscope tests. For her, refractometer, microscope, and specific gravity were enough to confirm that all the twenty five gems were synthetic flame-fusion blue sapphires.

She picked another ten unknown blue stones. She was enjoying the challenge like a gem detective. They weighed 4.85carats, 5.50carats, 2.98carats, 5.00carats, 3.99carats, 7.80carats, 6.00carats, 8.99carats, 8.00carats and 4.90carats respectively. With a loupe, she began to study all the ten oval stones, their color, shape, cut, brilliance, luster and their life. The crown looked too shallow with a knife edge girdle plane indicating the possibility of an assembled gem. The polariscope tests confirmed they were all double refractive (DR). Later, she proceeded to check their refractive indices (RI), and the result was 1.762-1.770 with a consistent birefringence of .008. The big surprise came when she began to study the stones under a microscope. After careful observation, it was found that the crown was a colorless sapphire, which showed needle-like inclusions, fingerprints, crystals confirming its natural status. Then when she turned to the pavilion it was discovered that all the ten blue stones had curved growth lines and gas bubbles confirming their synthetic status. The specific gravity (SG) was 4.00. She decided to skip fluorescence and spectroscope test. Finally, the ten stones were identified as corundum-doublets(assembled gems)—the crown being colorless sapphires and pavilion synthetic flame-fusion blue sapphires.

After making notes in a worksheet, she began to concentrate on the remaining five unknown blue stones. After a initial observation she weighed the gems. They were 4.78 carats, 5.00carats, 6.35carats, 6.85carats, and 8.00carats respectively. All were oval mixed cut. She decided to test the 4.78carat stone. Polariscope test indicated it was a double refractive(DR)stone. Refractive index(RI) test indicated it was an over-the-limit (OL) stone. With the help of microscope she saw crystal inclusions, and strong doubling of the back facets. The specific gravity (SG) was 4.70. After spectroscopic examination, it was identified as a high-type zircon.
She then picked up the 5.00carat stone. Polariscope test indicated the stone was double refractive (DR). Since the stone looked violetish blue, she decided to use the dichroscope and later found out that the stone had strong trichroism. Refractive index was 1.691-1704 with a birefringence of .008. Microscope observation revealed the stone had crystals, fingerprints, and a few needle-like inclusions. The specific gravity (SG) was 3.30. She decided to skip fluorescence and spectroscope tests. Finally, the unknown stone was identified as tanzanite (blue zoisite).

Then she picked up the 6.35carat stone. After observing the color, luster, brilliance she decided to skip polariscope and instead measured the stones refractive index (RI). It was 1. 762-1.770. The specific gravity was 4.00. The big surprise came after observing the stones with a microscope. The stones had more than enough flux fingerprints and platinum platelets—to confirm it was a synthetic flux blue sapphire. She decided to skip fluorescence and spectroscopy tests. The 6.85carat stone looked a bit dull. The stone was slightly greenish blue. Polariscope test confirmed it was a double refractive (DR) gem. Refractive index (RI) was 1.624-1.644. The specific gravity (SG) remained 3.08. Microscope observations showed doubling, crystals, and fingerprints.

She decided to skip spectroscope and fluorescence tests. Finally, the stone was identified as blue tourmaline (indicolite). The last 8.00carat stone had a life of its own. The blue gem had brilliance and luster, but there was something deceptive. That’s what she was going to find out. Polariscope tests confirmed it was double refractive (DR). Refractive index (RI) was 1.762-1770 with .008 birefringence. Specific gravity was 4.00. Microscopic observations showed fingerprints, needles, tiny crystals, and color concentrations at facet junctions. Immediately she put the stone in an immersion cell with 3.32 heavy liquid to study its color distribution. She didn’t carry out further tests. The stone was finally identified as surface diffusion-treated blue sapphire.

She made some notes on a worksheet. Meanwhile, George was busy talking loudly on his cell-phone to someone, and from the conversation she concluded that he was talking some serious business. She decided to leave him alone for a while so that she had enough time to compile the results on a laptop for future identification. She had a copy of the gemstones identification ready for him to view. She knew he wouldn’t look happy, and wondered at the reaction of the crook who had tricked him in Hong Kong. But most important of all, she was happy and enjoying her new work, and wondered whether all that was happening in her life was for good.

He returned quickly after the phone conversation to be with her. As he was reading the results, he couldn’t believe his eyes that he had been tricked by a close friend. It was a lot of money given the size of the stones. Immediately he switched on his cell-phone and called Hong Kong. He listened patiently, as he wrote down the name in his diary.

Now he had something more to worry about. He had a meeting with Jeffrey at a restaurant off Silom. He briefed Carly about his plans, and instructed her to be with him in disguise, because it was going to be an important meeting. He also gave her a map in case she got lost. Timing was more important for him. She had nothing to lose. Before leaving, he tossed a small leather bag with instructions. Her expression was precise as she opened it. BANG! BANG! BANG!