Micro-World Gems & Gemology, Spring 2016, Vol. 52, No. 1

Shrinkage “Footprint” in Rose Quartz

Footprint-shaped iron hydroxide deposit in quartz
This 0.98 mm yellowish brown footprint-shaped epigenetic deposit of iron hydroxide was discovered in a pale pink rose quartz from Madagascar. Photomicrograph by Nathan Renfro; field of view 2.38 mm.

Rose quartz is a widely distributed gem material. The specimen shown in was mined from pegmatites near the village of Tsaramanga, located in the Antananarivo province of Madagascar, and fashioned into a 34.11 ct rectangular step cut. It featured decorative epigenetic iron-colored debris that had been deposited in an extensive surface-reaching fracture. One of these debris patterns vividly calls to mind a dinosaur footprint left behind in soft mud.

It appears that the fine particulate debris was suspended in water and subsequently deposited in the crack as a wet solution. As the water dried, the resulting shrinkage pattern formed as only the particles were left behind, a mechanism very similar to the formation of water spots when raindrops dry on a smooth glassy surface. So now “footprints” joins “fingerprints” in our inclusion lexicon.

John I. Koivula is the analytical microscopist at GIA in Carlsbad, California.