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| Registros recuperados: 14 | |
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| Schweizer, C.R.. |
| The Vaterländisches Museum in Prague was officially founded in 1822 by Caspar and Franz Sternberg as a manifestation of Bohemian nationalism. It aimed at 1) the education of the public, 2) the sponsorship of Bohemian scientific and cultural research, and 3) the economical utilization of scientific knowledge. Under these aspects also the development of the oryctognostic collection of the museum should be regarded. In 1818, private mineral collections were donated. After its official opening in 1822, the united collections were split into two parts, a systematic and a local native collection. The first was basically distinguished by a prominent sortiment of gems, particularly by the typical garnet species and varieties, furthermore by the meteorites of... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 19th century; Bohemia; Museum; Collections; Research; Mineralogy; 38.30. |
| Ano: 2004 |
URL: http://www.repository.naturalis.nl/record/215469 |
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| Lagerwey, A.A.F.. |
| A new instrumental method for spectrographical detection of particularities of crystal fields around optically active ions, such as the trivalent chromium ion, was applied to an investigation of red magnesium-spinels from the Ratnapura gem gravels; also from Kangaiyam in India and some other sources for comparison. The method is characterized by analysis of luminescence spectra in the red and near infrared ranges excited by a concentrated flux of blue radiation, and analysed with a spectrograph of considerable optical power. Spectrograms are enregistered on photographic material of high resolving power; they reveal multiplet structures and intensity-distributions of component lines. Slight variations in spectral structure are significant for the detection... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1974 |
URL: http://www.repository.naturalis.nl/record/317401 |
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| Lagerwey, A.A.F.. |
| A selection of well developed apatite crystals of different habit and colour, originating from the tungsten-tin deposits of Panasqueira in Portugal, were analyzed by means of non-destructive optical methods. Phenomena of pleochroism, absorption and luminescence line-spectra, broadband-spectra and phosphorescence were studied. On the basis of extensive and systematic data, obtained from more than sevenhundred polarized spectrophotograms, registered of about seventy apatites from different types of deposit, and of a whole range of fluorapatites, doped with lanthanides and transition elements, it was possible to define the particular type of crystalfield and the nature and quantity of a number of trace elements, present in the fluorapatite from Panasqueira.... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/317463 |
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| Anastasenko, G.F.; Krivovichev, V.G.; Golynskaya, O.A.. |
| The Mineralogical Museum of the St.-Petersburg State University is housed in the building of the ‘Twelve Colleges’. It accomodates some of the most ancient mineralogical collections of Russia. The university mineral collection took its origin from a Mineralogical Cabinet of a Teacher’s Seminary, which was established in 1783. J.G. Georgi (1729-1802) was commissioned to collect minerals for the institute and he can be considered the founder of the museum. The history of enlarging and enriching the mineral collection is inextricably related with 19th century celebrities and their private collections. At the beginning of the 19th century, when the Seminary was transformed into a Pedagogical Institute, the collection of the Mineralogical Cabinet included in... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Minerals; Collections; 38.30. |
| Ano: 2004 |
URL: http://www.repository.naturalis.nl/record/215333 |
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| Zwaan, P.C.. |
| Both rhodolite and almandine garnets occur in Umba. The rhodolites have no special properties by which they can be distinguished from other garnets in the pyrope-almandine series, except their rose-red colour. Hence a distinctive name is unnecessary. Rutile appears to be the most frequent mineral inclusion in rhodolite, whereas in almandine both apatite and rutile are common. Corundums of different colours occur. Green corundums owe their colour to iron, while blue corundums have a high Ti and a low Cr content. Common inclusions are rutile, pyrrhotite and apatite, whereas graphite especially is found in deep violet corundums. The inclusions in both the garnets and the corundums are not characteristic of this locality. The properties of emerald green and... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1974 |
URL: http://www.repository.naturalis.nl/record/317404 |
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| Wegen, G. van der. |
| The present study deals with polyphase deformed and metamorphosed basic rocks from the Blastomylonitic Graben. The Blastomylonitic Graben is one of a number of meso- to catazonal complexes of probably Precambrian age in north-western Spain and northern Portugal. The results of the present study are obtained by application of the following methods: optical-mineralogical research, electronprobe microanalysis, X-ray powder diffraction and chemical whole-rock analysis. It is stated that the metabasites are originally of one, mainly bi-mineralic, rock type, altered by polymetamorphism. The successive phases of metamorphosis and deformation are differently developed locally and belong to two orogenies. The protolith was a rock, in which granoblastic... |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1978 |
URL: http://www.repository.naturalis.nl/record/317533 |
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| Zwaan, J.C.. |
| As one of the most valuable gemstones, emeralds are known to occur in several countries of the world, such as Colombia, Zambia, Brazil, Pakistan, Afghanistan, Russia, Madagascar and Zimbabwe. The emerald deposits at Sandawana, Zimbabwe, are described, the emeralds from this deposit characterised and a model of emerald formation presented; this is compared with existing models. The emeralds from Sandawana, Zimbabwe, show relatively constant physical properties, with high refractive indices and specific gravities. They are characterized by laths and fibres of amphibole, both actinolite and cummingtonite. Other common inclusions are albite and apatite. Rare, opaque and chromium-rich inclusions constitute a new variety of ilmenorutile. Compared to emeralds... |
| Tipo: Article / Letter to the editor |
Palavras-chave: Emerald; Sandawana; Zimbabwe; Gemmology; Petrology; Geothermometry; Geochronology; 38.30. |
| Ano: 2006 |
URL: http://www.repository.naturalis.nl/record/209632 |
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| Zwaan, P.C.; Arps, C.E.S.. |
| Three cut sphenes, originating from the Tissamaharama area in Sri Lanka, are described. Their properties are compared with those of gem quality sphenes from Capelinha, Brazil. There is hardly any difference between the chemical data of the major elements and physical properties of the specimens of these two sources. Even the inclusions are very similar. It is the first time that fine gem quality sphene has been reported from Sri Lanka. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/317475 |
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| Minina, E.L.. |
| Study of written sources in archives sometimes allows to restore the history of collections. A good example is the Alexander the First collection. In 1819, de la Harpe had sent an Etruscan vase to Alexander I as a gift, and had received a collection of Russian minerals in return. Alexander’s collection, totaling 1031 samplesaccording to the catalogue of 1874, consists of five sections: salts, stones, metals, combustible minerals, and rocks. The collection of Russian minerals presented by Alexander the First in 1820 to La Harpe is completely preserved to the present day and is exhibited at the Lausanne Natural History Museum. |
| Tipo: Article / Letter to the editor |
Palavras-chave: Mineralogical collection; Alexander the First; La Harpe; Etruscan vase; 38.30. |
| Ano: 2004 |
URL: http://www.repository.naturalis.nl/record/215466 |
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| Buurman, P.. |
| Fossil driftwood from Sarmatian (Late Miocene) gravel deposits near Yakuplu, Turkey, ranges between lignitic and opaline. Opalization occurred in various stages of decay. The stage of decay of the wood and the eventual admixture of detritic clay influenced the crystallinity and the dehydration characteristics of the opal. Opals influenced by the host rock seem to have montmorillonitic suprastructures. Opalization was probably the result of the weathering of volcanic ash layers in the overlying strata. |
| Tipo: Article / Letter to the editor |
Palavras-chave: 38.30. |
| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/317409 |
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| Registros recuperados: 14 | |
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