From the Greek "di," meaning "two," and "opsis," meaning "appearance." The crystal's cross-section shows two distinct faces depending on angle. One stone, two countenances.

A calcium-magnesium silicate of the pyroxene group. Sometimes found within kimberlite—the volcanic rock that hosts diamonds—making it a pathfinder mineral in diamond exploration. Not a diamond, but a signal that one may be near.

Sourced from Brazil, Russia, and Pakistan. Russian chrome diopside, coloured by chromium, shows a deep, saturated green. Mined from Siberian ground, its colour resembles a frozen conifer forest.