Winter 2023 - Volume 59, Issue 4
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This 0.69 ct alexandrite showed a stellate structure due to cyclic crystal twinning and pleochroism, producing a kaleidoscope effect when rotated. These photomicrographs were taken with a single polarizer placed above the stone and a white diffuser below the stone to highlight the color. Photomicrographs by Makoto Miura; field of view 9.80 mm.
“Kaleidoscope” in Alexandrite

Pleochroic colors caused by cyclic twinning produce a kaleidoscope effect in alexandrite.

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A “sun spangle” created in amber as a result of rapid cooling. Photomicrograph by Aamir Sayed; field of view 1.5 mm.
“Sun Spangle” in Amber

Heat treatment leaves a stunning circular stress fracture in amber.

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A feather in a 0.30 ct diamond with I<sub>1</sub> clarity resembled an alligator. Photomicrograph by Raju Jain; field of view ~3 mm.
Distinctive Feather in Diamond

A feather observed in a natural diamond resembles a large reptile.

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When light reflects from this crystal in a 1.01 ct diamond, the halo resembles a colorful butterfly. Photomicrograph by Tejas Jhaveri; field of view 2.90 mm.
Exquisite Butterfly in Diamond

A crystal inclusion with a stress halo resembles a colorful butterfly in a 1.01 ct diamond.

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A cross pattern observed in this DiamondView image of a 0.31 ct D-color type IIa diamond. Image by Priyanka Kadam.
Cross in Natural Diamond

DiamondView imaging revels a cross-shaped fluorescence pattern in a natural diamond.

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Numerous metal sulfide crystals scattered throughout a 3.05 ct Fancy Light gray diamond. Photomicrograph by Michaela Damba; field of view 14.52 mm.
Spotted Diamond

A Fancy Light gray diamond hosts numerous metal sulfide crystals.

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Tubular three-phase inclusions with albite (Ab) at each end in a natural Colombian emerald. These inclusions are oriented parallel to the <em>c</em>-axis of the crystal. Photomicrograph by Javier Toloza; field of view 0.95 mm.
Unusual Inclusions in Natural Emerald from Chivor

Tubular three-phase inclusions are observed in a Colombian emerald.

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A greenish blue octahedral crystal of gahnospinel found in Sri Lankan blue sapphire. Photomicrograph by Yusuke Takamura; field of view 3.81 mm.
Octahedral Gahnospinel Crystal in Sri Lankan Blue Sapphire

A rare octahedral gahnospinel crystal is observed in Sri Lankan sapphire.

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Hollandite crystals inside a natural amethyst from Bahia, Brazil. Photomicrograph by Liviano Soprani; field of view 2.20 mm.
Hollandite in Amethyst

A spectacular display of hollandite crystals is captured within an amethyst cabochon.

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Figure 1. A view through the girdle displayed one of the lighter violet pleochroic colors of the iolite host, revealing a mix of monazite and zircon inclusions surrounded by yellow radiation halos. Note the colorless cores in the larger halos. Photomicrograph by Emily Jones; field of view 3.64 mm.
Yellow Radiation Halos in Iolite (Cordierite)

Zircon, monazite, and apatite inclusions surrounded by yellow halos are observed in an iolite cabochon.

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