Stone, minerals and semiprecious of the world stone
Other: Petrified fossilized wood -->rus

   Diagnostic cart.

   Crystal structure amorphous
   Hardness on the Mohs scale 5-7
   Specific unit weight mass 1,9-2,5
   Cleavage non-existent
   Fracture, break padman
   Colors different
   Colors in powder triturate white
   Glance (glitter, glare) waxen

   Silicification wood of a tree consists of mixture of minerals of silica - opal chalcedony, rarer than quartz - in variable correlations, an opal prevails more frequent (a "woody opal" is pseudomorphosis on wood). It is a fossil, tree, converted into stone, as collectors-amateurs talk not fully correctly, because the organic components of tree never transform directly in stone, but retire, deputized a silica with formation of pseudomorphosis.

   Fossils are well saved only in those cases, when trees or their parts at once after dying off screen quickly, recovered the fine-grained sinking. Then circulatory waters gradually dissolve and take away organic component parts of wood, deputizing its mineral matters, consequently, there is not transformation, but substitution. Sometimes it flows so slowly, that elements of underlying structure of tree are annual rings, structure of cellulose, even motions of larvae - inherited pseudomorphosis of silica. From other side, in the process of silicification there are quite new patterns. Colouring of pseudomorphosis usually unattractive, grey or brown, but sometimes is soft red, rose, hazel, yellow or even blue, to dark blue and violet. Polishing and polish underline a color, doing him more juicy.

   Okremnevshaya wood, in-use as a carpentry stone, is opaque or slightly transparent. Its colouring changes from by sulphur to chestnut, even red, and yellow, rose and violet. Glance (glitter, glare) waxen. In some standards it is possible to look (along lengthening) after a typical for wood fibred structure and concentric rings on a perpendicular cut.

   Origin provenance genesis.

   Changes which silicification wood appeared as a result of took a place during cuttings-off of time from two centuries to million years. In these periods the forests were exposed to the action of different natural catastrophes.

   The disappointed trees were carried the strongest floods and bury very much far from a soil-site. Their barrels were recovered the layers of fallouts, arriving at hundreds of meters of power. The water circulating in this environment enriched silicon resulted in formation of pseudomorphosis, when substituted for a carbon (basic element of organic matter) silicon.

   Pseudomorphosis appeared due to a dense microcrystalline quartz (diaspore), microcrystalline fibred quartz (chalcedony) and amorphous aquated silica (opal).

   Deposit minefield mine field occurrence subsoil.

   By the most known mestome, where found out such fossil trees, there is the "petrifying forest" in Kholbruke, the state is Arizona (USA). The petrifying barrels of araucaria are there found long a to 65 m and by a diameter to 3 m. On a cut the structure of tree прочитывается due to alternation of red, yellow, violet and chestnut tints. As early as one deposit, in Virdzhin Velli (the state is Nevada), silicification wood is developed as raw material for the arts and crafts of different type.

   Found out shallow deposits and in other countries, for example, in Egypt, Argentina, Uruguay and France (mountains of Overn'). In Italy there are beds of окремневшего tree in Sonth Sardinia.

   Known deposit in the world is the famous petrified forest near Kholbruka in the state Arizona (USA). Here found out the accumulation of the petrified barrels of trees - pine-trees of family by araucaria monkey-puzzle length a to 65 m and in to 3 m. thick About 200 million years back brought these logs here from different places, and then they were recovered the layer of fallouts by power in a few honeycombs of meters. In time weathering processes freed part of silicification logs and their wreckages from surrounding rocks. Nowhere in more the world the petrified tree does not have such magnificent colourings, as in Arizona. On purpose save this unique on the beauty natural object a district was declared in 1962 By a national park Petrifild-forest ("Petrified forest").

   More shallow deposits of the petrified tree meet on all of continents. Egypt (Dzhel'-mokatam near Cairo) and Argentina supply with materials of good value (Patagoniya). The pieces of silicification tree from Virdzhin-velli (state is Nevada, USA) demonstrate the wonderful opal game of flowers. The petrified tree is used mainly for making of the articles of rock-cutting art and decorative wares (table top, ash-trays, supports for books, paper-weight), rarer for jeweller aims.

   In the CIS the petrified tree be found in Western Ukraine, CIS (near-by Lvov) and in Zakavkaz'e (Goderdzskoe deposit in Adzhariya, Sariarskoe - in Armenia), on Ural and in Sonth Kazakhstan, on Kamchatka and in Seashore (Russia, CIS).

   Use, practical application, deployment.

   Fossil wood is larghetto used on jeweller business for beads and cabochon. Some its differences are very popular among collectors.

   Varieties.

   Gagat is a dense variety of brown coal - Petrified fossilized wood of conifers, widespread in Europe approximately 180 million years back. It is opaque material, intensively-black color, exceptionally easy and soft. His most considerable deposits - in England, in the area of Uitbi, in Sonth Yorkshire. It is known also in France, Germany, United States and Russia. From гагата on jeweller business make beads, process fasings or cabochons. It is also used for implementation of intaglios.

   Gagat got the name to down the river in South-west Turkey. It an organic product is bituminiferous coal, well accepting a polish. Velvety waxen brilliance is characteristic, sometimes present inclusion Pyrite. Electrified at a friction. Districts of booty: before is England (Uitbi in гр. Yorkshire), now is Spain (Asturiya), France (Odd), USA (state of Quarter-deck, Colorado, USA). Lathed. Used in mournings decorations, for making clear, decorative objects and gems. Imitated other types of coal (by an anthracite, boghead), glass, ebonite, onyx.

   Keinel'skiy coal (кеннель) serves as the substitute of гагата. The name results from English candle is a candle, because from a beeswax, extracted from such coals, before did candles. Bogheads bed together with close-burning. They burn well, rich in volatiless (before from them got a coal-gas). Consist mainly of spores and pollen of plants. Due to the homogeneity and durability of cannel well lathed ordinary joiner's instruments; a polish gives him strong brilliance.