JEWELRY-QUALITY MODIROVAL AMMONITE, MADAGASCAR
Wood tin is a little-known and poorly studied kind of jewelry stones. This article gives information on mineral composition and gemology of jewelry-quality species of wood tin of Dominion Creek gold placer, Canada. The placer occurs in the primary gold-bearing area of Canada—Klondike known since the late 19th century. The placer is alluvial and valley, it was formed during the Quaternary period. Wood tin is an associate component of the placer and is connected with the rhyolitic tin deposits. The internal structure of wood tin is governed by the graded-zonal alteration of dark-brown, brown and light-brown layers of spherolitic-texture cassiterite. By the data of X-ray phase analysis, wood tin is mostly composed of cassiterite, to 97%, also quartz and potash feldspar are present. The optical–petrographic and electron probe research shows that wood tin is formed by cassiterite crystals of coarse to cryptocrystalline size, with different contents of impurity elements. Wood tin contains many pores. Color zonality of wood tin is conditioned by structural features and concentration of Fe. Various coloring and texture of wood tin in combination with high hardness and brilliant luster allows the mineral to compete with widely known gem stones. The jewelry-quality wood tin can be extracted as a by-product during mining of tin deposits and gold placers, which makes it a highly profitable kind of semi-precious raw material.
: 553.8: 553.45 (71)DOI
: Petrochenkov D. A.
Petrochenkov D.A., Candidate of Geological and Mineralogical Sciences,
Assistant Professor, e-mail: firstname.lastname@example.org,
Russian State Geological Prospecting University named after Sergo Ordzhonikidzе
(MGRI-RSGPU), 117997, Moscow, Russia.Key words
Wood tin, cassiterite, gold, gen stones, tin deposits, placers.References
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