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Usability of obsidian with special refraction as an ornamental stone by bonding with epoxy resin

Rızaoğlu Tamer, Camuzcuoğlu Murat

Systemy Wspomagania w Inżynierii Produkcji

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2022

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Vol. 11, iss. 2

96--103

EN

Ornamental stones have been used quite a lot from past to present, and they are produced both naturally and synthetically in terms of visuality, durability and rarity. Naturally used ornamental stones are divided into two different classes as precious and semi-precious, and obsidian with two different colors belonging to the Nemrut volcanics used in the study is classified as semi-precious stones. Obsidian is a volcanic glass, showing a special fracture (conchoidal) and fracture surfaces give the rock a distinctive shine. In this study, obsidian was classified by breaking in different sizes (8-4.75 mm, 4.75-2 mm and 2-0.6 mm) in order to achieve this brightness. While black obsidian shards were obtained from 4.75-2 mm in size, brown obsidian shards were obtained from 2-0.6 mm shards and chose with the help of tweezers. Obsidian fragments with both colors were bonded with epoxy resin mixed at a ratio of 2:1 (epoxy and hardener) and placed in jewelry apparatus. The known durability properties and gloss of epoxy and the gloss on the broken surfaces of obsidian have been highlighted, and it has been observed that obsidian which has been used with different cutting and polishing techniques until now, can be obtained as a new product by using binder material. It is suitable to be used as an ornamental stone in jewelry making as a result of binding the obsidian fragments with epoxy by making use of the shines that occur on the fractured surfaces of the obsidian. In addition, it has been revealed that new products can be obtained as a result of bonding many natural rocks and minerals by using different binding materials.

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Gemstones of eastern Kazakhstan

Chlachula Jiri

Geologos

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2020

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Vol. 26, No. 2

139--162

EN

An overview is presented of gemstones from eastern Kazakhstan in terms of their geographical distribution, geological provenance and genesis, gemmological characteristics, historical use and current applications. Locally occurring precious, semi-precious and decorative stones were extracted and traded along the northern part of the Silk Road that traversed the area in earlier historical times. Currently, non-metallic minerals, which largely originate from mafic igneous and metamorphic bodies of the Altay and Kalba Mountains of Kazakhstan, still are insufficiently known and exploited industrially only marginally. For the present study, selected depositories of coloured stones at the Mineralogy Museum of the East Kazakhstan State Technical University were used, supplemented by the newly collected material during personal fieldwork in the southern Altay between 2005 and 2015. Standard documentation of the gemstones selected is provided, alongside with their known occurrence sites and an evaluation of the perspective gemstone-bearing deposits with respect to regional morphostructural bedrock characteristics. The most precious gemstones include topaz, corundum (sapphire and ruby), beryl (emerald and aquamarine), coloured tourmalines, agates as well as diamonds. Despite the great variety, the majority of these traditionally most valued stones are currently commercially not viable, unlike high-quality decorative stones.

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Planning of quarrying operations of ornamental stones in northern Portugal by using cut-off grade as a criterion of quality control

Torres V. F. N., Da Gama C. D., Singh R. N., Qiang X.

Archives of Mining Sciences

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2011

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Vol. 56, no 4

711-725

EN

The planning of quarrying operations of ornamental stones has unfortunately not achieved much success, in the past, in relation to quarry planning and control. The present paper presents an innovative methodology utilizing the concept of cut-off grade as a quality control criterion of nepheline syenite production in the Monqchiue quarry during the production of ornamental stones blocks of four different qualities. This innovative management approach is considered to be the first successful attempt of ornamental stone quarry management with excellent results.

PL

W przeszłości, w odniesieniu do planowania i kontroli wydobycia, planowanie operacji wydobywania kamieni ozdobnych nie należało do udanych. W pracy zaprezentowano nowatorską metodę wykorzystania koncepcji wartości brzeżnej jako kryterium kontroli jakości w produkcji sjenitu nefelinowego w kamieniołomie Monquichiue w trakcie produkcji bloków kamieni ozdobnych o czterech różnych właściwościach. To nowatorskie podejście uznawane jest za pierwszą udaną próbę zarządzania wydobyciem kamieni ozdobnych przynoszącym doskonałe rezultaty.