with Phantom growth from the
Erongo Mountains, Namibia|
Nambibia, at the south west end of the African continent, is well known for its richness in minerals. Certainly, Tsumeb is the most famous location there. However, the Erongo Mountains near the Brandtberg-complex, produce excellent specimens, such as this wonderful Amthyst. It shows lighter and darker zones, which display "crystals in the crystal". This phenomeneon is called phantom crystal.
sprinkled nice Markasite crystals
|Amethyst from the Erongo
Mountains, Namibia. |
These crystals show pronounced phantom growth with alternating Amethyst and Smokey quartz colors. Moreover, many of the Eronog specimen also show so-called "negative crystals", which is a cavity inside the crystal with the exact shape and faces of a quartz crystal. Frequently cavities inside the crystals are filles with liquids and gas (so-called bubbles that move when the crystal is turned). These fluids and gases can be analyzed in terms of growth conditions and origin.
|Fadenquartz from Wana
Faden is the German word for a string. In these quartzes one can see a white string (Faden) in the middle of the crystal with the individual quartz crystals growing perpendicular to the Faden. In the present case the indivisual crystals also spiral along the axis of the faden. Such spiraled or twisted specimen are called a "Gwindel".
Rosequartz can form large amorphous masses, but rarely crystalizes.
The best crystalized Rosequartz specimen come from Brazil and are relatively small in size
(this crystal ~1.5 cm)
|Smokey Quartz from the
Little Three Mine,|
This mine produced not only Spessartite Garnets, Topaz, and Tourmalines, but also very nice, clear Smokey quartzes. The color of Smokey quartzes often comes from a natural source of radioactivity, which causes defects in the crystal lattice.
Rutil included in Quartz.
Sometimes a mineral forms in a pocket and is later "overgrown" by another mineral forming later in the crystalization sequence. Here, Rutil (Titaniumoxide) formed first, the quartz crystalized later.
|The Zillertal is also very well known for its Szepter- and Window-Amthyst and its Hematit-roses (Eisenrosen), which can be found in the Mörchnerkaar and the Saurüssel. The Amthyst quite frequently do not have the most intense violett colors, but they impress more by their shape. Here we show a Sezepter of about 5 cm hight. In fact, it appears that there was first a nomal Quarz, which was then overgrown by a doubly terminated pale Amethyst. What makes this specimen special are the fine hairs of Rutil and two blades of Brookite, which can be seen in the upper part of the crystal.|