This small piece was languishing in our cabinets until I hit it with a very strong longwave lamp. Only then, did the bright yellow zincite appear. Quite stunning actually. The zincite is also an interesting red in natural light. Portions of the willemite has an interesting yellow glow to them as well. If the piece was from somewhere other than Sterling, it might be something altogether different. Shown in longwave, shortwave and natural.