Dolomite cast with Calcite
4.3 x 3.4 x 2.2 CM (miniature)
new year 2021
One of the many odd but amazing things found over the years in Tsumeb were hollow Dolomite casts. These are replacements or encrustations of earlier minerals which have since disappeared. Sometimes the casts have then been overgrown with other minerals as well. The forms are quite diverse and entire collections have been made of the many shapes, colors and associations. This miniature cast is a pale green color and is overgrown with gem clear, colorless Calcite rhombs. The walls are typically thin and the whole specimen is a delicate hollow structure. Looks great from any angle, an attractive example of a mineral oddity.
Dolomite - iridescent
3 x 2.4 x 2.3 CM (small miniature/ large thumbnail (toenail))
new year 2021
An unusual and attractive thumbnail of Dolomite crystals from Tsumeb with iridescent sheen. An older piece originally labelled "Cobaltoan Dolomite, Tsumeb SWA", however, this does not look at all like the usual Cobalt coloring and doubt the accuracy of that. This is however unusual looking for Tsumeb the crystals are sharp, slightly curved and have reddish-purple highlights.
A delicate and fine Dolomite cast having two separate generations. The large scalenohedral shapes are hollow having just a thin skin of Dolomite that had covered what were likely Calcites, now long gone. The matrix is an earlier generation itself just a thin skin of tiny sparkling crystals. The Dolomite casts from Tsumeb were found in many exotic forms are are very collectable. This one is in perfect condition, esthetic and looks fine from all sides.
A fine transparent cluster of Dolomite crystals from the classic Spanish locality of Eugui, Navarre. An uncommon matrix piece, the crystals are up to 4 CM in diameter and very sharp, undamaged. Dolomite is a very common mineral and crystals are not rare at all, but sharp, gem clear Rhombs like this are really only found at this one locality and they are very rare in such quality. Some minor dark zoning is seen but overall these are white to colorless and mostly transparent. The penetration twinning is textbook sharp and clear, an excellent piece found in 1998.
Dolomite on Quartz
Williamsville Quarry, Poplar Bluffs
6 x 4 x 3.2 CM (cabinet)
A very colorful Dolomite, bright yellow to Orange bladed crystals contrast well with a dark druzy quartz matrix. I have not seen another specimen like this piece from this locale, better known for Calcites. Super showy and in fine condition.