gems, spinel, Tanzania, inclusions, diopside, phlogopite, edenite

Gemology is a forensic science, and often what we don’t know can be as interesting as what we do know. Recently, the authors encountered a fascinating spinel. The owner noted that the stone (reportedly from Myanmar, formerly Burma) contained an inclusion feature with a bubble inside. Closer inspection revealed a negative crystal or cavity that indeed contained a mobile bubble (see above). With gentle heating from the warmth of the microscope’s light bulb, the authors were able to see the bubble expand and contract.