Etch Marks, Negative Crystals, and Etch Tubes in Spinel from Madagascar
A spinel from Madagascar, mixed in with a parcel of blue sapphire, exhibited an array of internal features.
Iridescent Inclusion in Tanzanite
A tanzanite displayed crystallographically aligned, vividly iridescent colors resulting from fine separations along the stone’s cleavage planes.
Mobile Fluorite in Quartz
This violet-colored fluorite crystal was free to move in its octahedral void, as seen in four different positions. Photomicrographs by Nathan Renfro; field of view 7.18 mm.
Quarterly Crystal: Quartz with Axinite
The first visual record of axinite inclusions in quartz published in the gemological literature.
Andradite in Andradite
An iridescent Japanese andradite contained an iridescent inclusion of andradite, creating an arresting optical phenomenon.
Growth Blockages in Cat’s-Eye Beryllonite
A rough colorless beryllonite showed an unusually sharp separation between two regions, caused by minute inclusions deposited during growth that prevented growth of the host mineral.
Sphalerite in Topaz
Tourmaline Termination
Unusual Growth Zoning in Beryl
A striking aquamarine specimen showed a strongly saturated secondary growth layer.