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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

Aamir Sayed, January 26, 2024

Heat treatment leaves a stunning circular stress fracture in amber.

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

Michaela Damba, January 26, 2024

A Fancy Light gray diamond hosts numerous metal sulfide crystals.

A view through the table of a padparadscha sapphire displayed this jagged suspended crystal, likely a metal sulfide, featuring a rare texture. Photomicrograph by Courtney Robb; field of view 2.90 mm.

Spiky Inclusion in Padparadscha Sapphire

Courtney Robb, January 26, 2024

An inclusion with a metallic luster is observed in a pinkish orange padparadscha sapphire.

Figure 1. A rock crystal pendant measuring 48.5 × 31.2 × 8.8 mm with a white cross inclusion. Photo by Tsung-Ying Yang.

Rock Crystal with Cross Inclusion Exhibiting Brownian Motion

Shu-Hong Lin, Tsung-Ying Yang, Kai-Yun Huang, and Yu-Shan Chou, January 26, 2024

Numerous two-phase inclusions form a cross in a rock crystal pendant.

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)

Tyler Smith and Emily Jones, January 26, 2024

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

Figure 1. Weighing 20.57 ct and measuring 37.10 mm in length, this doubly terminated, heavily etched spodumene crystal contains chromium as its coloring agent or chromophore. Photo by Adriana Robinson.

Quarterly Crystal: Hiddenite from Idaho

John Koivula, Nathan Renfro, and Maxwell Hain, January 26, 2024

Sail-shaped etch features provide proof that a sample sold as aquamarine is actually a spodumene crystal.

A pseudo-icosahedral crystal of pyrite in a 2.88 ct Colombian emerald. Photomicrograph by Taku Okada; field of view 1.01 mm.

Pseudo-Icosahedral Pyrite in Colombian Emerald

Taku Okada, January 26, 2024

A 2.88 ct Colombian emerald plays host to a metallic yellow pyrite crystal.

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

Makoto Miura, January 26, 2024

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

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

Javier Toloza, Luis Gabriel Angarita, Holman Alvarado, and Camilo Andrés Betancur, January 26, 2024

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

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

Hollandite in Amethyst

Liviano Soprani, January 26, 2024

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

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