| In the late Middle Ages massive amount of Baryt which phosphoresced when it was gently heated, were discovered in Italy. This stone was named after its place of discovery "Pietra fosforica di Bologna" (phosphorescent Bologna stone) and was of great interest to alchemists. Although the name baryte ha ... moreIn the late Middle Ages massive amount of Baryt which phosphoresced when it was gently heated, were discovered in Italy. This stone was named after its place of discovery "Pietra fosforica di Bologna" (phosphorescent Bologna stone) and was of great interest to alchemists. Although the name baryte has been assigned centuries later, it may be assumed that the Bologna stone is the first description in the literature. A portrait about this famous mineral by Peter Seroka. |
| The term used in the plural "pyrites" has often been misused in the past or in common for marcasite, chalcopyrite, pyrrhotite and other yellow to brass-colored minerals. The word pyrite is derived from the Greek "pyrites lithos" (derived pyr = fire and lithos = stone) and describes a characteristic ... moreThe term used in the plural "pyrites" has often been misused in the past or in common for marcasite, chalcopyrite, pyrrhotite and other yellow to brass-colored minerals. The word pyrite is derived from the Greek "pyrites lithos" (derived pyr = fire and lithos = stone) and describes a characteristic of the mineral, when rubbing against steel or flint (flint) to generate sparks. In prehistoric tombs pyrite concretions and unrolled pyrite where found, which supposed to be used for lighting a fire. (Article in German) |
| Aragonite is a calcium carbonate, chemically identical with calcite. The mineral calcite, however, differs from Aragonite due to its internal crystal structure. While the crystal system of calcite is trigonal, the system of aragonite is rhombic. Dense masses of small aragonite crystals are difficul ... moreAragonite is a calcium carbonate, chemically identical with calcite. The mineral calcite, however, differs from Aragonite due to its internal crystal structure. While the crystal system of calcite is trigonal, the system of aragonite is rhombic. Dense masses of small aragonite crystals are difficult to distinguish from calcite, but they are larger, they show a distinct habit. A lot of chapters in this portrait will give you much more details about this interesting mineral. Written and investigated by Peter Seroka. (Article in german) |
| Die Bildung der Achate am Karrenberg ist äußerst komplex und hochinteressant. Erkennbar wird dies zum einen an der Abfolge der Mineralisationen im Mandelbereich. In der direkten Umgebung der größeren Mandeln kann man mit viel Glück einen kleinen Graphiteinschluss ausma ein Beitarg von u.a. Klaus Sch ... moreDie Bildung der Achate am Karrenberg ist äußerst komplex und hochinteressant. Erkennbar wird dies zum einen an der Abfolge der Mineralisationen im Mandelbereich. In der direkten Umgebung der größeren Mandeln kann man mit viel Glück einen kleinen Graphiteinschluss ausma ein Beitarg von u.a. Klaus Schäfer chen, der von einigen Sammlern durch angenommene Bildung von Kohlenstoffgasen als mitverantwortlich für die Hohlraumbildung angesehen wird. Diese Graphiteinschlüsse wurden bei der Bildung des Schlotes, als dieser durch tiefer gelegen karbonische Schichten brach, mitgerissen. Die von aussen nach .... Ein Beitrag von Klaus Schäfer |
| This portrait explains the background to the most fascinating natural events on Earth, how are volcanoes build and what causes eruptions, lava flows and lahars. A rich picture book with some stunning shots invites you to dive into the fascinating world of magmatic phenomena. (Article in german) ... moreThis portrait explains the background to the most fascinating natural events on Earth, how are volcanoes build and what causes eruptions, lava flows and lahars. A rich picture book with some stunning shots invites you to dive into the fascinating world of magmatic phenomena. (Article in german) |
| For Mineral collectors who travel in their vacation to the mining area of La Union, the mina Precaución is an easy to reach and in 2010 a worthwhile target to collect attractive pieces with hemimorphite, calcite and more minerals on contrast rich matrix. Equipped with helmet, forehead lamp, chisel ... moreFor Mineral collectors who travel in their vacation to the mining area of La Union, the mina Precaución is an easy to reach and in 2010 a worthwhile target to collect attractive pieces with hemimorphite, calcite and more minerals on contrast rich matrix. Equipped with helmet, forehead lamp, chisel and hammer nice pieces can be rescued easily, taking into account the security rules for mining visits. |