New find of skeletal Galena from the 9th of September Mine. This is true skeletal Galena (not the manufactured specimens from about 10 years ago), only the second time in 20 years that they have been found. The Chalcopyrite and Sphalerite add color and contrast. Undamaged.

New find of skeletal Galena from the 9th of September Mine. This is true skeletal Galena (not the manufactured specimens from about 10 years ago), only the second time in 20 years that they have been found. The Chalcopyrite and Sphalerite add color and contrast. Undamaged.

Large, bright Chalcopyrite crystals to 3cm associated with Quartz, Sphalerite, and Galena. Highly aesthetic with damage limited to a few Quartz crystals.

Single Dravite crystal exhibiting the 'Usambara effect' color change (named after nearby mountains). This is a different type of color change than the Alexandrite effect, where the color changes in different types of lighting. In this case, the Dravite crystal appears green in normal lighting, however when a single light source is transmitted through the crystal, at a certain thickness, a sudden color shift from green to red is observed, while less thick areas remain green. Well terminated, complete crystal. This is often demonstrated by taking thin slices of crystals. If, for instance, the critical thickness is 3mm, you can take two slices that are 2mm thick each, and each will appear to be green. If you overlap them slightly, creating a combined thick ness of 4mm the area that is overlapped will appear red. This crystal is dark but very transparent, gem quality. Transparent red with strong backlighting.

Single Dravite crystal exhibiting the 'Usambara effect' color change (named after nearby mountains). This is a different type of color change than the Alexandrite effect, where the color changes in different types of lighting. In this case, the Dravite crystal appears green in normal lighting, however when a single light source is transmitted through the crystal, at a certain thickness, a sudden color shift from green to red is observed, while less thick areas remain green. Well terminated, complete crystal. This is often demonstrated by taking thin slices of crystals. If, for instance, the critical thickness is 3mm, you can take two slices that are 2mm thick each, and each will appear to be green. If you overlap them slightly, creating a combined thick ness of 4mm the area that is overlapped will appear red. This crystal is dark but very transparent, gem quality.Transparent red with strong backlighting.