US 201601 13363A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2016/0113363 A1 DYMSHTS et al. (43) Pub. Date: Apr. 28, 2016

(54) HEATRESISTANTSYNTHETIC UEWELRY Publication Classification MATERAL (51) Int. Cl. (71) Applicants: Olga Sergeevna DYMSHITS, St. A44C27/00 (2006.01) Petersburg (RU); Alexander CO3CIO/00 (2006.01) Alexandrovich ZHILIN, St. Petersburg (52) U.S. Cl. (RU); Karen Khorenovich AVAKYAN, CPC ...... A44C27/001 (2013.01); C03C 10/0018 Moscow (RU) (2013.01) (72) Inventors: Olga Sergeevna DYMSHITS, St. (57) ABSTRACT Petersburg (RU); Alexander A heat-resistant synthetic jewelry material having a transpar Alexandrovich ZHILIN, St. Petersburg ent, semitransparent or nontransparent composite nanocrys (RU) talline material on the basis of nanosized oxide and silicate crystalline phases. The material includes at least one of the (21) Appl. No.: 14/890,843 following crystalline phases: spinel, quartz-like phases, sap phirine, enstatite, petalite-like phase, cordierite, willemite, (22) PCT Fled: Jun. 25, 2013 Zirconium, rutile, Zirconium titanate, Zirconium dioxide with a content of ions of transition elements, rare-earth elements (86) PCT NO.: PCT/RU2013/OOO538 and precious metals of from 0.001 to 4 mol%. One of the S371 (c)(1), crystalline phases is additionally quartz-like Solid solutions (2) Date: Nov. 12, 2015 of lithium magnesium Zinc aluminosilicates with a virgilite or keatite structure. The composition is selected from the fol (30) Foreign Application Priority Data lowing components, SiO2, Al-O, MgO, ZnO, LiO, PbO, ZrO, TiO, NiO, CoO, CuO, CrOs. BiO, FeO, MnO, May 13, 2013 (RU) ...... 2013 122741 CeO2, Nd2O, ErOs. PrO and Au. US 2016/0113363 A1 Apr. 28, 2016

HEATRESISTANTSYNTHETIC UEWELRY crystals, and/or Smoky quartz, and/or chrysoprase, and/or MATERAL carnelian. In the invention, the silicate glass with the melting temperature of 500-950° C. is used. The composition material 0001. The present invention is related to the production of is produced by Stacking together the wastes of precious and synthetic materials for jewellery intended for the substitution semiprecious Stones using the silicate glass with very low of natural precious Stones. melting temperature. Parts produced by this procedure have 0002 Synthetic materials are traditionally used in jewel low mechanical strength. They cannot be used in serial pro lery for the Substitution of natural gemstones. Synthetic gem duction as their appearance cannot be reproduced. Due to the stones can be divided into two groups. The synthetic gem difference in the coefficients of thermal expansion of the stones of the first group have the same composition and silicate matrix and fillers made of precious stone wastes, the physical properties as natural precious stones. Among them, resultant composite material has low thermal shock resis there are amethyst, citrine, Smoky quartz, alexandrite, ruby tance. Above all, a convenient and inexpensive technology of and spinel fabricated by Czochralski process, synthetic jewellery manufacturing “casting with stones' cannot be corundum and spinel manufactured by Verneuil process, applied to Such materials due to the low melting temperature hydrothermal emerald. of the silicate glass. 0003 Artificial, synthetic gemstones of the second group 0007 RU Pat. 2,162,456 published on 27 Jan. 2001 with imitate the appearance, particularly, the colour of natural indexes MIK C04B5/14 and C01B33/113 outlines the gemstones while having quite different compositions and manufacturing of synthetic material with the noble opal struc physical properties. Moreover, some of them do not exist in ture. Synthetic material is produced by the following stages: nature. The examples of such materials are yttrium aluminum 1. preparing the monodisperse Suspension of amorphous garnet, gallium gadolinium garnet, and phianite doped with silica with globule sizes of 140-600 nm.: 2. precipitating, oxides of rare-earth and transition elements. The significant layer by layer the precipitate and drying at 100-150° C. for disadvantage of synthetic gemstones is inhomogeneity of 10-30h, after that, further drying the precipitate at a pressure their colouration caused by the gradual changes of the inten of 1-10 Pa.; 3. after drying, annealing the precipitate at the sity of colouration from the beginning of crystallization to its temperature of 350-400° C. and the pressure of 15-45 MPa in end. This inhomogeneity owes to the fact that the concentra the atmosphere of water vapor and tetraethoxysilane; and 4. tion of colouring dopants in melts (or Solutions) usually filling the precipitate with silica sol and heat-treating at 400 changes in the course of the crystallization due to selective 600° C. for 1-2 h. entering the crystals by the dopants. Because of this, as crys 0008. This method is very difficult, labor- and time-con tals grow, the dopants concentration in them can change. The Suming, the product cost is very high. In addition, by this most intense inhomogeneity is the inhomogeneity of green, method, obtaining materials of various phase assemblage, blue, and brown phyanites, blue Sapphire, green and blue structures and colours is impossible. The main drawback of yttrium aluminum garnet, etc. It is common knowledge that this material is that it is very brittle and cracks during dehy growing of these crystals, their cutting and Sorting by the dration, which occurs quickly especially upon heating. It is colour are labor consuming and very difficult from the manu worth noting that the processes are rather intensive at as low facturing point of view. Besides, many coloured synthetic temperature as 100° C. gemstones produced under reducing conditions change their 0009 RU Pat. No 2,215,455 published on 10 Nov. 2003 colour upon heating in the open air (due to the oxidation of the with indexes MIIK A44C17/00, C30B31/02, C30B33/02 colouring agent). presents the method for colouring natural and synthetic gem 0004 Colourless and coloured glass (crystal glass, rhine stones. The method is intended for colouring the colourless stones), is widely used in bijouterie and in rather cheap jew and pale blue Sapphires, colourless topazes and quartz. The ellery. Glass is usually homogeneously coloured, however, it method consists of placing the grinded gemstones into a thin ranks below synthetic gems in terms of refractive index, glit cobalt oxide powder comprising a mixture of CoO and Co-O ter, hardness, density, and heat resistance. in the ratio of 1:1 mixed with ZnO in the ratio of 1:(0.25-3). 0005. The main disadvantage of many synthetic materials The mixture is heat-treated in the oxidizing conditions at and glasses is their low thermal shock resistance, i.e., they fail 900-1250° C. to maintain integrity at sharp temperature drops. They often 0010. The parts prepared by said method are coloured only crack being unable to withstand the thermal shock. This dis on the SuRUace. Their additional grinding and polishing is advantage prevents material grinding and polishing using a impossible because the thin coloured layer becomes dam high-speed processing. A convenient and inexpensive tech aged. This method provides only blue colouring, other colour nology of jewellery manufacturing “casting with stones' can tints cannot be achieved. not be applied to Such materials. O011 RU Pat. No 2,253,706 published on 20 Jan. 2005 with indexes MIIK C301 29/20, C30B28/00, C30B31/02, BACKGROUND OF THE INVENTION C30B33/02 outlines the jewellery material—synthetic poly 0006 RU Pat. No 2,336,005 published on 20 Oct. 2008 crystalline corundum “Mariite' and its method of synthesis. under indexes MIIK A44C27/00, B44C5/06, B44F9/04, The material consists of alumina, colour dopants and paraffin C04B30/00, CO3C6/02, B28D5/00 claims the mixture of the wax used as a binder. The colour dopants are molybdenum, raw materials for manufacturing the parts of jewellery wolfram, neodymium, erbium, chromium oxides. The pro intended to Substitute the precious stones. The mixture com duction of the material used as parts for jewellery is made by prises the crushed silicate glass and wastes of rubies and/or forming the mixture with the use of molding machines under Sapphires, and/or emeralds, and/or alexandrites, and/or noble a pressure of 4 atm. followed by the Subsequent firing in spinels, and/or euclase, and/or topazes, and/or aquamarines, furnaces of continuous or periodic action. Then the coloured and/or heliodors, and/or garnets, and/or amethysts, and/or translucent potsherd is polished with diamond powder. This hyacinths, and/or cordierites, and/or turmalines, and/or rock method ensures only production of semitransparent material; US 2016/0113363 A1 Apr. 28, 2016

transparent material cannot be produced by this method, 0017. The technical result is achieved by the development which significantly reduces the variety of the final articles. In ofathermal shock resistant transparent, translucent or opaque addition, the obtained materials are of the limited range of material based on at least one of the following oxide or colours: there are no blue, green, yellow, brown materials. silicate crystalline phases: spinel, Sapphirine, enstatite, pet The nature of the binding agent paraffin wax prevents alite-like phase, and/or magnesium aluminotitanates, cordi material operation at elevated temperatures. erite, willemite, Zircon, rutile, Zirconium titanate, Zirconium 0012. It is well known that glass-ceramics with near Zero dioxide, with a content of at least one of the following ions of thermal expansion coefficients are produced by the controlled transition and rare earth elements and noble metals in an crystallization of solid solutions with B-quartz (B-eucryptite) amount from 0.001 to 4.0 mol %, in which, as opposed to the structure in glasses of the lithium aluminosilicate system. prototype, there is an additional crystalline phase, Solid solu This method is used in production of coloured transparent tion of lithium-magnesium-zinc-aluminosilicate with Virgi thermal shock resistant kitchen ware, cooking tops, windows lite (B-quartz) or keatite structure. of metallurgic and heating furnaces. Researches from Corn 0018. The composition of the proposed material is ing Inc., USA, developed glass compositions converted to selected from the following components (mol. %): SiO, glass-ceramics by heat-treatment and coloured to various 45-72: AlO-15-30; MgO 0.1-23.9; ZnO 0.1-29; tints of yellow, brown and purple colours. U.S. Pat. No. 3,788, LiO–1-18; PbO 0.1-7.0; ZrO 0.1-10; TiO, 0.1-15; 865, MIIK C03C10/14, published in 1974, describes pro NiO 0.001-4.0; CoO 0.001-3.0; CuO 0.001-40; duction of transparent coloured glass-ceramics, containing CrO 0.001-1.0: BiO, 0.001-3.0; FeO, 0.001-3.0; B-eucryptite crystals and coloured with the following MnO, 0.001-3.0; CeO, 0.001-3.0; NdO, 0.001-3.0; dopants: VO, MnO, Cr-O, FeO, CuO, NiO and ZnS. ErO 0.001-3.0; PrO 0.001-3.0; Au–0.001-1.0. However, the resulting materials have a relatively low hard 0019. The thermal-shock-resistant synthetic transparent, ness, which is an important disadvantage for jewellery mate translucent or opaque nanocrystalline composite material for rials. U.S. Pat. No. 5,491,115, published on 13 Feb. 1996 with jewellery is prepared from the compositions shown in Table 1. indexes MIIK C03C010/14, C03C010/12, outlines produc tion of purple-red and violet colour in transparent thermal TABLE 1 shock resistant material. However, all these materials have a relatively low hardness, which is an important disadvantage Component Concentration (mol%) for jewellery materials. SiO2 45-72 Al2O3 15-30 0013 RU Pat. No 2,42,6488, on 20 Aug. 2010 with MgO O.1-23.9 indexes MIIK A44C17/00, A44C27/00, the prior art, pre ZnO O. 1-29 sents the material with highhardness, chemical resistance and Li2O -18 colour resistance against thermal shock. This is a synthetic ZrO2 O. 1-10 transparent, translucent or opaque nanocrystalline composite TiO2 O. 1-15 PbO O. 1-7 material for jewellery based on at least one of the following NO O.OO1-4.O nanosized oxide or silicate crystalline phases: spinel, quartz CoO O.OO1-3.0 like phases, Sapphirine, enstatite, petalite-like phase, cordier CuO O.OO1-4.O ite, willemite, Zircon, rutile, Zirconium titanate, Zirconium Cr2O3 O.OO1-1.O Bi2O3 O.OO1-3 dioxide, with a content of ions of transition, rare earth ele Fe2O3 O.OO1-3.0 ments and noble metals in an amount from 0.001 to 4.0 mol MnO, O.OO1-3.0 % CeO2 O.OO1-3.0 Nd2O3 O.OO1-3.0 0014 Despite its unique properties, the material does not Er-O O.OO1-3.0 have an ultralow thermal expansion coefficient (CTE) (below PrO. O.OO1-3.0 30-107 K') which means that it does not have the required Au O.OO1-1.O high thermal shock resistance. The lack of the required high thermal shock resistance impedes the rapid machining, in where TiO, ZrO2. NiO, CoO, CuO, Cr-O, BiO, Fe2O, particular, the laser SuRUace treatment, and making holes MnO, CeO, Nd,0s, ErO, PrO, and Au are added above with lasers. The method of “casting with precious stones' 100% of the base composition. A body of the first five com cannot be used because the material that contains crystalline ponents listed in Table 1 ensures formation of the alumino phases with high thermal expansion coefficient can crack silicate network. PbO enters this network, increasing the during thermal cycling. Furthermore, its melting temperature refractive index of the material. TiO, and ZrO, are used a range of 1570-1640° C., which complicates refining and nucleating agents. NiO, CoO, CuO. CrOs. BiO, Fe2O, homogenization of glass using the standard glassmaking MnO, CeO2, Nd2O, ErOs. PrO and Au are colouring equipment and require high energy consumption. agents. 0015 Thus, among the analogues and the prototype there 0020. The technical solution is prepared as follows: is no material that would meet all the requirements of modern 1. Melting of the mixture of raw materials selected from the jewellery. starting components listed in Table 1, at the temperature of 200-300° C. above liquidus, at 1520-1550° C. SUMMARY OF THE INVENTION 2. Cooling of the glass melt to a temperature of 1300-1410° 0016. The object of the invention is to provide a jewellery C., shaping and annealing the material at 620-650° C., (this material having high thermal shock resistance and low CTE temperature corresponds to the viscosity of 10'-10' Pars). as compared with the known materials, including the proto 3. Converting the initial glass into a synthetic transparent, type, and to decrease the melting temperature to below 1570 translucent or opaque nanocrystalline composite material for C. jewellery by additional heat treatment: heating, at a tempera US 2016/0113363 A1 Apr. 28, 2016

ture of from 660 to 800° C., at which nucleation occurs, for schedules, have optical characteristics similar to those of the 1-24 hours, and forming, at a temperature of from 780 to main natural coloured minerals, demonstrate adaptability in 1200° C. for 1-24 hours, at least one of the following nanos production, have low coefficient of thermal expansion, high cale oxide and crystalline silicate phases: Solid solutions of hardness, chemical resistance and colour stability to thermal lithium-magnesium-zinc-aluminosilicates with Virgilite shock; their melting temperature is decreased as compared (B-quartz) or keatite structure, spinel, Sapphirine, enstatite, with the prior art. petalite-like phase, cordierite, willemite, Zircon, rutile, Zirco 0023 Components in the form of oxides and carbonates nium titanate, Zirconium dioxide. were mixed, milled to obtain a homogeneous batch; the batch 4. Cooling the synthetic transparent, translucent or opaque was inserted to the crucible made of quartz ceramics, which nanocrystalline composite material to the room temperature. was placed into the furnace. The batch was melted at a tem 0021 Ions of transition metals, rare earth elements and perature of 1520-1550° C. for about 6 hours while stirring noble metals in an amount from 0.001 to 4 mol.% provide with a stirrer made of quartz ceramics and then was cast into colouring of the material. a steel mold to form a transparent bar. 0022. The examples of compositions, heat treatment con ditions and properties of the proposed materials are given in THE BEST EXAMPLES Table 2. The table shows that the glass-ceramics of proposed compositions, prepared according to the listed heat-treatment 0024 TABLE 2 Sample No

1 2 3 Component Concentration (mol%) SiO2 45 S4.9 72 Al2O3 30 15 16 MgO 23.9 O.1 4 ZnO O.1 29 4 Li2O 1 1 4 ZrO, O.1 10 6 TiO2 15 3 O.1 PbO O.1 2 7.0 NO 4 1.O O.OO CoO O.OO1 O.OOS 3.OOO CuO O.OO1 O.OO1 O.OO Cr2O3 O.OO1 O.OO1 O.OO Bi2O3 O.OO1 O.OO1 O.OO Fe2O. O.OO1 O.OO1 O.OO MnO2 O.OO1 O.OO1 O.OO CeO2 O.OO1 O.OO1 O.OO Nd2O3 O.OO1 O.OO1 O.OO Er-O O.OO1 O.OO1 O.OO Pr2O3 O.OO1 O.OO1 O.OO Au O.OO1 O.OO1 O.OO Heat-treatment conditions 1 stage 660° C., 24h 800° C., 4h 770° C., 12 h. 2 stage 900° C., 24h 1000° C., 12h 1200° C., 1 h Colour Green, Green, Green, transparent opaque opaque i Thermal 1S.O 19.0 22.0 expansion coefficient (x107. C.) Glass melting 1540 1540 1550 temperature, C. Crystalline Solid solution of Solid solution of Solid solution of phases lithium-magnesium lithium-magnesium lithium-magnesium zinc-aluminosilicate zinc-aluminosilicate zinc-aluminosilicate with virgilite (B- with 3-spodumene with 3-spodumene quartz) structure (keatite) structure (keatite) structure Spinel Spinel Spinel Magnesium Zircon Cordierite aluminotitanates Petalite-like phase Rutile Zirconium titanate Zirconium dioxide Zirconium dioxide Sample No

4 5 6 Component Concentration (mol%) SiO2 45 S4.9 70 Al2O3 30 15 18

US 2016/0113363 A1 Apr. 28, 2016

TABLE 2-continued Crystalline Solid solution of Solid solution of Solid solution of phases lithium-magnesium- lithium-magnesium lithium-magnesium zinc-aluminosilicate zinc-aluminosilicate zinc-aluminosilicate with virgilite (B- with virgilite (B- with virgilite (B- quartz) structure quartz) structure quartz) structure Spinel Willemite Cordierite Magnesium Spinel Zirconium dioxide aluminotitanates Zircon Zirconium titanate Zirconium dioxide Sample No

7 8 Component Concentration (mol%) SiO, 45 S4.9 Al2O3 30 15 MgO 1O.O O.1 ZnO O.1 16 Li2O 14.9 14 ZrO2 O.1 10 TiO2 15 3 PbO O.1 2 NO O.OO1 1.O CoO O.OO1 O.OO1 CuO O.OO1 O.OO1 Cr2O3 O.OO1 O.OO1 Bi2O3 O.OO1 O.OO1 Fe2O3 O.OO1 O.OO1 MnO2 3.OOO O.OO3 CeO, O.OOO O.OOO Nd2O3 O.OO1 O.OO1 ErO3 O.OO1 O.SOO Pr2O3 O.OO1 O.OO1 Au O.OO1 O.OO1 Heat-treatment conditions 1 stage 680° C., 24h 780° C., 12 h. 800° C., 2 stage 820° C., 24h 900° C., 12 h. 1200° C., Colour Light-brown, Rosy, Rosy, transparent transparent opaque Thermal 2.0 S.O 21.0 expansion coefficient (x107, C.) Glass melting 1520 1S2O 1550 temperature, C. Crystalline Solid solution of Solid solution of Solid solution of phases lithium-magnesium- lithium-magnesium lithium-magnesium zinc-aluminosilicate zinc-aluminosilicate zinc-aluminosilicate with virgilite (B- with virgilite (B- with 3-spodumene quartz) structure quartz) structure (keatite) structure Spinel Spinel Cordierite Magnesium Zirconium titanate Zirconium dioxide aluminotitanates Zirconium dioxide Sample No

4 5 Component Concentration (mol%) SiO, 45 S4.9 Al2O3 30 15 MgO 12.9 O.1 ZnO O.1 12 Li2O 12 18 ZrO2 O.1 10 TiO2 15 O.1 PbO O.1 2 7.0 NO O.OO1 O.OO1 OOO1 CoO O.OO1 O.OO1 OOO1 CuO O.OO1 O.OO1 OOO1 Cr2O3 O.OO1 O.OO1 OOO1 BiO. O.OO1 O.OO1 OOO1 Fe2O3 O.OO1 O.OO1 OOO1 MnO2 O.OO1 O.OO1 OOO1 US 2016/0113363 A1 Apr. 28, 2016 6

TABLE 2-continued CeO2 O.OO1 O.OO1 OOO1 Nd2O. O.OO1 O.OO1 3.OOO Er-O O.OO1 O.OO1 OOO1 Pr2O3 O.OO1 O.OO1 OOO1 Au O.OO3 1.OOO OOO1 Heat-treatment conditions 1 stage 720° C., 6 h 700° C., 12 h. 750° C. 1 h 2 stage 1050° C., 24h 850° C., 12 h. 1200° C., 1 h Colour Purple, Red, Lilac, opaque transparent opaque Thermal 18.0 3.0 12.0 expansion coefficient (x107, C.) Glass melting 1520 1S2O 1550 temperature, C. Crystalline Solid solution of Solid solution of Solid solution of phases lithium-magnesium lithium-magnesium lithium-magnesium zinc-aluminosilicate zinc-aluminosilicate zinc-aluminosilicate with 3-spodumene with virgilite (B- with 3-spodumene (keatite) structure quartz) structure (keatite) structure Sapphirine Spinel Cordierite Enstatite Zirconium titanate Zirconium dioxide Magnesium Zirconium dioxide aluminotitanates

INDUSTRIAL APPLICABILITY which damages the integrity of the samples after the heat 0025 Introduction of SiO, in an amount less than sug treatment at the second stage. The duration of the heat treat gested does not lead to the formation of transparent material ment on the first stage which is more than 24 hours results in during glass melting, and the introduction of SiO in an crystallization of undesired crystalline phases and therefore amount greater than Suggested increases the melting tempera does not result in the desired colouration. ture of the melt to temperatures exceeding 1600°C., thus no 0027 Heat treatment of the samples in the second stage at standard glass-making equipment can be used for glass melt a temperature below 780° C. does not lead to crystallization ing. It impedes obtaining the pure glass melt. Introduction of of the desired phases, and therefore, does not result in the LiO in an amount Smaller and larger than the concentration desired colours. Heat treatment of the samples in the second range claimed prevents the obtaining of Solid solutions of stage at a temperature above 1200° C. leads to melting of the lithium-magnesium-zinc-aluminosilicate with Virgilite material. The duration of the heat treatment in the second step (B-quartz) or keatite structure, lowering the CTE of the mate which is less than 1 hour is unsufficient for crystallization. rial obtained. Introduction of Al-O, MgO, ZnO and LiO in The duration of the second stage heat treatment which is more an amount Smaller and larger than the concentration range than 24 hours results in the destruction of crystals and colour claimed, prevents the obtaining of transparent initial glass. loss. Introduction of PbO in amounts less than Suggested, does not 0028. The initial glass was heat-treated according to the lead to increasing refractive index of the material. Introduc schedules listed in Table 2. The characteristic of the crystal tion of PbO in an amount larger than the concentration range line phases was determined using X-ray diffraction analysis. claimed prevents the obtaining of transparent initial glass. The coefficient of thermal expansion and thermal shock resis Introduction of TiO, and ZrO in an amountless than claimed tance were measured as well. In each experiment, the initial prevents obtaining the solid monolithic material after the glass was heated to a first temperature plateau at a rate of 300° secondary heat-treatment. Introduction of TiO, and ZrO in C./hr, then was hold for a time sufficient to develop liquid an amount greater than claimed leads to crystallization of the phase separation, then the temperature was raised to a second glass melt during casting. Introduction of the colouring plateau at a rate of 300°C./hour, and the material was hold for agents NiO, CoO, CuO, CrOs. BiO, Fe2O, MnO, CeO. a time sufficient for crystallization of nanosized crystals of NdO, ErOs. PrO and Au in an amount less than claimed Solid solution of lithium-magnesium-zinc-aluminosilicates does not lead to material colouration. Introduction of NiO, with virgilite (B-quartz) structure or solid solution of lithium CoO, CuO, CrO, BiO, FeO, MnO, CeO, NdO. magnesium-zinc-aluminosilicates with B-spodumene (ke ErOs. PrO and Au in an amount greater than claimed leads atite) structure and/or spinel, and/or quartZ-like Solid solu to crystallization of the glass melt during casting. tions, and/or Sapphirine, and/or enstatite, and/or petalite, and/ 0026. Additional heat-treatment of the glass at the first or cordierite, and/or willemite, and/or magnesium stage at below 660° C. does not lead to liquid phase-separa aluminotitanates, and/or Zircon, and/or rutile, and/or Zirco tion and crystallization of titanium- and Zirconium-contain nium titanate, and/or Zirconium dioxide. The sample thus ing phases, ensuring nanoscale crystallization of the initial obtained was cooled to room temperature with the furnace. glass. Additional heat-treatment of the glass at the first stage 0029 Proposed material obtained by this method pos at above 800° C. leads to crystallization of large-size silicate sesses uniform colour, optical characteristics similar to the crystals that damages the integrity of samples. The duration of characteristics of the main natural coloured minerals and the heat-treatment at the first stage which is less than 1 hour manufacturable. A very important advantage of the material is does not result in the phase separation of the initial glass, its low coefficient of thermal expansion, hardness, chemical US 2016/0113363 A1 Apr. 28, 2016

resistance and colour stability to thermal shock, which allows, in particular, accelerated mode of grinding and pol ishing as well as permits using the method of “casting with precious stones', as not only the faceted samples do not crack in contact with the of silver or gold melt, but they’re also able to retain their colour. 1. A heat-resistant synthetic jewelry material comprising: a transparent, translucent or opaque composite nanocrys talline material on the basis of nanosized oxide and silicate crystalline phases, the material comprises at least one of the following crystalline phases: spinel, quartz-like phases, Sapphirine, enstatite, petalite-like phase, cordierite, willemite, Zircon, magnesium alumi notitanates, rutile, Zirconium titanate, Zirconium dioxide with a content of ions of transition elements, rare-earth elements and precious metals of from 0.001 to 4 mol%. wherein one of the crystalline phases is additionally quartz-like Solid solutions of lithium magnesium Zinc aluminosilicates with a virgilite or keatite structure, wherein the composition is selected from the following components, in mol %: SiO 45-72; Al-O 15-30; MgO 0.1-23.9; ZnO 0.1-29; Li2O–1-18; PbO 0. 1-7.0; ZrO, 0.1-10; TiO, 0.1-15; NiO 0.001-40; CoO 0.001-3.0; CuO - 0.001-4.0; CrO, 0.001-1. 0; BiO, 0.001-3.0; FeO, 0.001-3.0: MnO, 0. 001-3.0; CeO, 0.001-3.0; Nd2O, 0.001-3.0; ErO 0.001-3.0: PrO 0.001-3.0; Au–0.001-1.0. k k k k k