Glass materials and decorative items

Abstract

The present invention provides novel glass materials and decorative items whose color tone changes when exposed to different light sources. [Solution] A glass material containing, in mole percent, 0.1-20% Dy2O3, 0.1-20% Nd2O3, 0-80% SiO2+B2O3+Al2O3, 0-90% La2O3, and 0-90% Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2.

Description

Technical Field

[0001] The present invention relates to a glass material and an ornament.

Background Art

[0002] There is known glass whose color tone changes when exposed to different light sources. For example, a technique for customizing the color tone of glass by adding Pr2O3 or Ho2O3 to glass containing Nd2O3 has been proposed (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Materials whose color tone changes when exposed to different light sources may be used for ornaments because of their rarity. From the viewpoint of expanding the design diversity of ornaments, there is a demand for materials that exhibit a color tone different from the conventionally known color tones.

[0005] In view of the above, an object of the present invention is to provide a novel glass material and an ornament whose color tone changes when exposed to different light sources.

Means for Solving the Problems

[0006] Aspects of the glass material and the ornament for solving the above problems will be described.

[0007] The glass material of Embodiment 1 is characterized by containing, in molar percentages, 0.1-20% Dy2O3, 0.1-20% Nd2O3, 0-80% SiO2+B2O3+Al2O3, 0-90% La2O3, and 0-90% Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2.

[0008] The glass material of embodiment 2 is characterized in that, in embodiment 1, when irradiated with light using an LED light source having a peak wavelength in the range of 360 to 500 nm and when irradiated with light using a D65 light source, L * a * b * It is preferable that the color difference ΔE in the color system is 2.3 or greater.

[0009] The glass material of embodiment 3 contains Dy2O3 and Nd2O3, and when irradiated with light using an LED light source having a peak wavelength in the range of 360 to 500 nm, and when irradiated with light using a D65 light source, L * a * b * It is characterized by having a color difference ΔE of 2.3 or more in the color system.

[0010] In the glass material of Embodiment 4, it is preferable that the content of each of the oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce, Pr, Tb, Ho, or Er is less than 2% in any one embodiment from Embodiment 1 to Embodiment 3.

[0011] In the glass material of Embodiment 5, it is preferable that the refractive index nd is 1.5 or higher in any one embodiment from Embodiments 1 to 4.

[0012] The ornament of embodiment 6 is characterized by comprising a glass material of any one embodiment from embodiment 1 to embodiment 5. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide novel glass materials and decorative items whose color tone changes when exposed to different light sources. [Brief explanation of the drawing]

[0014] [Figure 1] These are the emission spectra of the LED light source and D65 light source used in the example. [Modes for carrying out the invention]

[0015] Preferred embodiments are described below. However, the following embodiments are merely illustrative, and the present invention is not limited to these embodiments.

[0016] The glass material of the present invention contains Dy2O3 and Nd2O3. Due to the inclusion of these components, the glass material of the present invention changes color when exposed to different light sources. For example, it exhibits a first color when exposed to an LED light source (e.g., an LED light source having a peak wavelength in the range of 360-500 nm), and a second color different from the first when exposed to a daylight light source (e.g., a D65 light source). Specifically, it exhibits a light purple color under daylight and a light green color under LED light. In one embodiment, the glass material of the present invention is characterized by containing, in molar percentages, Dy2O3 0.1-20%, Nd2O3 0.1-20%, SiO2+B2O3+Al2O3 0-80%, La2O3 0-90%, and Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 0-90%. The reason for this limitation of the glass composition is explained below. In the following explanations regarding the content of each component, unless otherwise specified, "%" means "molar percent".

[0017] Dy2O3 is a coloring component that has the effect of adjusting the color tone of glass materials. It also has the effect of increasing the refractive index of glass materials. The Dy2O3 content is preferably 0.1 to 20%. The lower limit of the Dy2O3 content is preferably 0.1% or more, 1% or more, 3% or more, and especially preferably 5% or more. The upper limit of the Dy2O3 content is preferably 20% or less, and especially preferably 15% or less. If the Dy2O3 content is too low, it becomes difficult to obtain the desired color tone change. It also becomes difficult to increase the refractive index of the glass material. If the Dy2O3 content is too high, the glass is more likely to devitrify. Also, the coloring becomes too strong and the visible range transmittance tends to decrease.

[0018] Nd2O3 is a coloring component that has the effect of adjusting the color tone of the glass material. The Nd2O3 content is preferably 0.1 to 20%. The lower limit of the Nd2O3 content is preferably 0.1% or more, 0.5% or more, and especially preferably 1% or more. The upper limit of the Nd2O3 content is preferably 20% or less, 15% or less, 10% or less, 5% or less, and especially preferably 3% or less. If the Nd2O3 content is too low, it will be difficult to obtain the desired color tone change. If the Nd2O3 content is too high, the glass will be prone to devitrification. Also, the coloring will become too strong and the visible light transmittance will tend to decrease.

[0019] From the viewpoint of adjusting the color of the glass material to a desired hue, the molar ratio Nd2O3 / Dy2O3 is preferably 1 or less, 0.9 or less, 0.5 or less, and particularly 0.3 or less. The lower limit of the Nd2O3 / Dy2O3 value may be 0.01 or more, and particularly 0.02 or more. Note that "Nd2O3 / Dy2O3" means the value obtained by dividing the Nd2O3 content by the Dy2O3 content.

[0020] The content of Dy2O3+Nd2O3 (total amount of Dy2O3 and Nd2O3) is preferably 0.2 to 40%. The lower limit of the Dy2O3+Nd2O3 content is preferably 0.2% or more, 0.5% or more, 1% or more, 3% or more, and especially preferably 5% or more. The upper limit of the Dy2O3+Nd2O3 content is preferably 40% or less, 30% or less, 25% or less, and especially preferably 20% or less. If the Dy2O3+Nd2O3 content is too low, it becomes difficult to obtain the desired color change. Also, it becomes difficult to increase the refractive index of the glass material. If the Dy2O3+Nd2O3 content is too high, the glass is more likely to devitrify. Also, the coloring becomes too strong and the visible range transmittance tends to decrease.

[0021] From the viewpoint of stabilizing vitrification, the content of SiO2+B2O3+Al2O3 (total amount of SiO2, B2O3, and Al2O3) is preferably 0-80%. The lower limit of the SiO2+B2O3+Al2O3 content is preferably 0% or more, 1% or more, 5% or more, and particularly preferably 10% or more. The upper limit of the SiO2+B2O3+Al2O3 content is preferably 80% or less, 70% or less, 60% or less, and particularly preferably 50% or less. If the SiO2+B2O3+Al2O3 content is too high, it becomes difficult to increase the refractive index. Therefore, from the viewpoint of particularly increasing the refractive index, the upper limit of the SiO2+B2O3+Al2O3 content is preferably 40% or less, 30% or less, and particularly preferably 20% or less.

[0022] SiO2 forms the glass skeleton and is a component that facilitates vitrification. The SiO2 content is preferably 0-80%. The lower limit of the SiO2 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the SiO2 content is preferably 80% or less, and especially preferably 70% or less. If the SiO2 content is too high, it becomes difficult to increase the refractive index. Particularly from the viewpoint of increasing the refractive index, the upper limit of the SiO2 content may be 40% or less, 30% or less, and especially preferably 20% or less.

[0023] B2O3 is a component that forms the glass skeleton and facilitates vitrification. The B2O3 content is preferably 0-80%. The lower limit of the B2O3 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the B2O3 content is preferably 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, and especially preferably 20% or less. If the B2O3 content is too high, it becomes difficult to increase the refractive index. Also, weather resistance tends to decrease.

[0024] Al2O3 is a component that forms a glass skeleton and expands the vitrification range. It also has the effect of improving chemical durability. The Al2O3 content is preferably 0 to 80%. The lower limit of the Al2O3 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the Al2O3 content is preferably 80% or less and 70% or less. If the Al2O3 content is too high, the melting temperature tends to rise. Also, it becomes difficult to increase the refractive index. Particularly from the viewpoint of increasing the refractive index, the upper limit of the Al2O3 content may be 40% or less, 30% or less, and especially preferably 20% or less.

[0025] La2O3 is a component that forms the glass skeleton and also increases the refractive index. The La2O3 content is preferably 0-90%. The lower limit of the La2O3 content is preferably 0%, 1%, 5%, 10%, and especially preferably 20% or more. The upper limit of the La2O3 content is preferably 90% or less, 80% or less, 70% or less, and especially preferably 63% or less. Too much La2O3 content can actually make vitrification more difficult.

[0026] From the viewpoint of increasing the refractive index of the glass, the content of Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 (total amount of Nb2O5, Ta2O5, Gd2O3, ZrO2, and TiO2) is preferably 0-90%. The lower limit of the content of Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 is preferably 0% or more, 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, and especially preferably 50% or more. The upper limit of the content of Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 is preferably 90% or less, and especially preferably 80% or less. If the content of Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 is too high, vitrification becomes difficult. Therefore, if stability of vitrification is prioritized, the upper limit of the content of Nb2O5+Ta2O5+Gd2O3+ZrO2+TiO2 may be 40% or less, 30% or less, 20% or less, or especially 10% or less.

[0027] Nb2O5 is a component that has a significant effect on increasing the refractive index and is a component that easily improves the dispersibility of glass materials. When glass is highly dispersed, it is easier for a rainbow-colored sparkle called "fire" to appear, improving the aesthetic appearance of decorative items. The Nb2O5 content is preferably between 0% and 90%. The lower limit of the Nb2O5 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the Nb2O5 content is preferably 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, and especially preferably 20% or less. If the Nb2O5 content is too high, vitrification becomes difficult.

[0028] Ta2O5 is a component that has a significant effect on increasing the refractive index. The Ta2O5 content is preferably 0-90%. The lower limit of the Ta2O5 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the Ta2O5 content is preferably 90% or less, 80% or less, 70% or less, and especially preferably 60% or less. If the Ta2O5 content is too high, vitrification becomes difficult. Particularly from the viewpoint of stabilizing vitrification, the upper limit of the Ta2O5 content is preferably 30% or less, 20% or less, and especially preferably 10% or less.

[0029] Gd2O3 is a component that easily increases the refractive index. It also has the effect of improving weather resistance. The Gd2O3 content is preferably 0 to 90%. The lower limit of the Gd2O3 content is preferably 0%, 1%, 5%, and especially preferably 10% or more. The upper limit of the Gd2O3 content is preferably 90% or less, 80% or less, 70% or less, and especially preferably 60% or less. If the Gd2O3 content is too high, vitrification becomes difficult. Particularly from the viewpoint of stabilizing vitrification, the upper limit of the Gd2O3 content is preferably 30% or less, 20% or less, and especially preferably 10% or less.

[0030] ZrO2 is a component that increases the refractive index. Furthermore, because it forms a glass skeleton as an intermediate oxide, it is also a component that easily broadens the vitrification range. The ZrO2 content is preferably 0-90%. The lower limit of the ZrO2 content is preferably 0%, 1%, 5%, and particularly preferably 10% or more. The upper limit of the ZrO2 content is preferably 90% or less, 80% or less, 70% or less, and particularly preferably 60% or less. If the ZrO2 content is too high, the melting temperature tends to rise. Especially from the viewpoint of reducing the melting temperature and improving mass productivity, the upper limit of the ZrO2 content is preferably 30% or less, 20% or less, and particularly preferably 10% or less.

[0031] TiO2 is a component that has a significant effect on increasing the refractive index and also has the effect of improving chemical durability. It is also a component that easily improves the dispersibility of glass materials. The TiO2 content is preferably between 0% and 90%. The lower limit of the TiO2 content is preferably 0%, 1%, 5%, 10%, and especially 20% or more. The upper limit of the TiO2 content is preferably 90% or less, 80% or less, 70% or less, 60% or less, and especially 50% or less. If the TiO2 content is too high, the transmittance of visible light tends to decrease.

[0032] From the viewpoint of increasing the refractive index of the glass while improving the stability of vitrification, the content of La2O3+Nb2O5+ZrO2+TiO2 (total amount of La2O3, Nb2O5, ZrO2, and TiO2) is preferably 0 to 90%. The lower limit of the La2O3+Nb2O5+ZrO2+TiO2 content is preferably 0% or more, 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, and especially preferably 60% or more. Particularly from the viewpoint of obtaining glass with a refractive index of 2.0 or higher, the La2O3+Nb2O5+ZrO2+TiO2 content is preferably 70% or more, and especially preferably 80% or more. The upper limit of La2O3+Nb2O5+ZrO2+TiO2 is preferably 99% or less, and especially preferably 90% or less.

[0033] From the viewpoint of increasing the refractive index of the glass while enhancing the stability of vitrification and achieving a desired color difference, the content of La2O3+Nb2O5+ZrO2+TiO2+Dy2O3 (total amount of La2O3, Nb2O5, ZrO2, TiO2, and Dy2O3) is preferably 0.1 to 90%. The lower limit of the content of La2O3+Nb2O5+ZrO2+TiO2+Dy2O3 is preferably 0.1% or more, 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, and especially preferably 60% or more. Particularly from the viewpoint of obtaining glass with a refractive index of 2.0 or more, the content of La2O3+Nb2O5+ZrO2+TiO2+Dy2O3 is preferably 70% or more, and especially preferably 80% or more. Furthermore, the upper limit of La2O3+Nb2O5+ZrO2+TiO2+Dy2O3 is preferably 99% or less, and particularly preferably 90% or less.

[0034] From the viewpoint of broadening the vitrification range and improving chemical durability, the content of MgO+CaO+SrO+BaO+ZnO (total amount of MgO, CaO, SrO, BaO, and ZnO) is preferably 0-10%, and particularly preferably 0-5%. If the content of MgO+CaO+SrO+BaO+ZnO is too high, the refractive index tends to decrease. The content of MgO, CaO, SrO, BaO, and ZnO is preferably 0-10%, 0-5%, and particularly preferably 0-3%, respectively.

[0035] From the viewpoint of lowering the melting temperature and improving mass productivity, the content of Li2O+Na2O+K2O (total amount of Li2O, Na2O, and K2O) is preferably 0-10%, and particularly preferably 0-5%. If the content of Li2O+Na2O+K2O is too high, the refractive index tends to decrease. The content of Li2O, Na2O, and K2O is preferably 0-10%, 0-5%, and particularly preferably 0-3%, respectively.

[0036] The glass material of the present invention may also adjust the color tone by containing a coloring component composed of an oxide of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce, Pr, Tb, Ho, or Er. These coloring components may be contained alone or in combination of two or more. However, if the coloring becomes too strong, the visible light transmittance may decrease, and the desired glow and fire may not be obtained. Therefore, when it is desired to suppress the coloring by the above oxides, the content of each of the above coloring components is preferably less than 2%, less than 1%, less than 0.5%, particularly less than 0.1%. For example, the content of the coloring component composed of Pr oxide (Pr2O3 or Pr6O 11 ) and the coloring component composed of Ho oxide (Ho2O3) is preferably less than 2%, less than 1%, less than 0.5%, particularly less than 0.1% respectively. When intentionally causing coloring by the above oxides, the content of each of the above coloring components may be 0% or more, particularly 0.1% or more.

[0037] Sb2O3 may be contained as a fining agent. However, in order to avoid coloring and considering the environmental aspect, the content of Sb2O3 is preferably 1% or less, particularly 0.5% or less.

[0038] Considering the environmental load, it is preferable that PbO and As2O3 are not substantially contained. In the present invention, "not substantially contained" means that it is not intentionally contained as a glass composition, and does not exclude the inclusion of unavoidable impurities. Objectively, it means that the content is less than 0.1% in mol%.

[0039] When the glass material of the present invention is irradiated with light using an LED light source having a peak wavelength in the range of 360 to 500 nm and when irradiated with light using a D65 light source, L * a * b *The color difference ΔE in the color system is preferably 2.3 or higher, 2.5 or higher, 2.8 or higher, and especially 3 or higher. The upper limit of the color difference ΔE is not particularly limited, but for example it may be 20 or less. When the color difference ΔE is within the above range, the change in color tone when exposed to different light sources becomes clear, making it suitable for use in decorative items, etc. The LED light source is preferably, for example, 2600 to 7100K, and especially preferably 3800 to 5500K. The color temperature of the LED light source conforms to the correlated color temperature specified in JIS Z 9112.

[0040] Here, the color difference ΔE is L * a * b * This is the color difference in a color system and can be calculated using the following formula (1).

[0041] ΔE={(L * D65 -L * LED ) 2 +(a * D65 -a * LED ) 2 +(b * D65 -b * LED ) 2 )} 0.5 ...Formula (1)

[0042] In equation (1), L * D65 a * D65 and b * D65 This is the L value when light is irradiated onto a glass material using a D65 light source. * a * b * It is a value. L * LED a * LED and b * LED This refers to the L value obtained when irradiating a glass material with light using an LED light source having a peak wavelength in the range of 360-500 nm. * a *b * It is a value. Note that L * is the brightness index (L axis = 0 to 100), a * and b * This represents the chromatic Neck exponent (a-axis = -60 to +60, b-axis = -60 to +60). * a * b * The value may be measured directly using a colorimeter, but since it is difficult to measure accurately in highly transparent materials such as glass, it may be calculated from the glass's reflectance spectrum, color matching functions, and the light source's emission spectrum. Specifically, the XYZ color system value (tristimulus value) is calculated from the glass's transmission spectrum, color matching functions, and the light source's emission spectrum, and this tristimulus value is then calculated L * a * b * You may convert it to a value.

[0043] L * D65 and L * LED The absolute value of the difference (ΔL) * The lower limit of ) is preferably 0.1 or greater, 0.5 or greater, and especially preferably 1 or greater. ΔL * The upper limit is not particularly limited, but it is preferably, for example, 20 or less, 10 or less, and especially 5 or less.

[0044] a * D65 and a * LED The absolute value of the difference (Δa * The lower limit of ) is preferably 0.1 or greater, 0.5 or greater, 1 or greater, and especially 3 or greater. Δa * The upper limit is not particularly limited, but it is preferably 20 or less, and more preferably 10 or less. Note that in the glass material of the present invention, Δa * The larger the value, the larger the color difference ΔE tends to be, and the more pronounced the color changes when exposed to different light sources become.

[0045] b * D65 and b * LED The absolute value of the difference (Δb) *The lower limit of ) is preferably 0.1 or higher, 0.2 or higher, 0.5 or higher, 1 or higher, and especially 3 or higher. Δb * The upper limit is not particularly limited, but it is preferably, for example, 20 or less, 10 or less, and especially 5 or less.

[0046] The glass material of the present invention preferably has a refractive index nd of 1.5 or higher, 1.7 or higher, 1.8 or higher, 1.9 or higher, and particularly 2.0 or higher. This increases the refractive index difference between the inside and outside (atmosphere) of the glass material, making it easier for light to be reflected inside the glass material. As a result, it becomes easier to obtain sufficient brilliance for decorative purposes. There is no particular upper limit to the refractive index, but from the viewpoint of stabilizing vitrification, it is preferable that it be 2.6 or lower, 2.5 or lower, and particularly 2.4 or lower. Note that the refractive index nd refers to the measured value relative to the helium lamp d line (587.6 nm).

[0047] The glass material of the present invention can be suitably used as decorative items such as jewelry, works of art, and tableware. For example, it is preferably used in decorative items such as rings, pendants, earrings, and bracelets. In other words, it is preferable that the decorative items of the present invention include the glass material of the present invention as described above. The glass material of the present invention may also be used, for example, as a quasi-gemstone.

[0048] The shape of the glass material of the present invention is not particularly limited and can be a sphere, ellipsoid, polyhedron, etc. It may also be a shape having so-called faceted surfaces (for example, a shape with faceted cuts such as brilliant cut, step cut, or mixed cut), or a shape without faceted surfaces (for example, a shape with a cabochon cut). [Examples]

[0049] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0050] [Table 1]

[0051] [Table 2]

[0052] [Table 3]

[0053] [Table 4]

[0054] First, raw materials were mixed to produce the glass compositions shown in Tables 1 and 2, and raw material batches were prepared. These batches were then melted until homogeneous. The melting temperature was set to 1400-2200°C. After rapidly cooling and solidifying the molten glass, glass materials were obtained by annealing near the glass transition temperature (550-850°C). The refractive index (nd) and L2 of the obtained glass materials were measured using a D65 light source and an LED light source with a peak wavelength in the range of 360-500 nm. * a * b * The values ​​were determined for each sample. In addition, the appearance of the sample was visually inspected under each light source, and the color tone was evaluated.

[0055] The refractive index (nd) was measured using a precision refractometer (Shimadzu KPR-2000) after polishing the glass sample at a right angle. The refractive index was evaluated based on the measurement value against the helium lamp d-line (587.6 nm). The results are shown in Tables 1 and 2.

[0056] When using a D65 light source and an LED light source with a peak wavelength in the range of 360-500 nm, L * a * b * The values ​​were calculated using the transmission spectrum of the glass sample, the emission spectrum of the D65 light source, the emission spectrum of the LED light source, and the CIE 1931 XYZ color matching function, respectively. Specifically, the XYZ color system values ​​(tristimulus values) were calculated from the transmission spectrum of the glass, the color matching function, and the emission spectrum of the light source, and these tristimulus values ​​were then calculated using L * a * b* The values ​​were converted to numerical values. The results are shown in Tables 3 and 4. The transmission spectrum was measured in the range of 380 to 780 nm using a UV-Vis-Near-Infrared spectrophotometer (V-670, manufactured by the Japan branch) on a 3 mm thick glass sample with mirrored surfaces on both sides. Figure 1 shows the emission spectra of a D65 light source and an LED light source with a peak wavelength in the range of 360 to 500 nm.

[0057] As shown in Tables 3 and 4, the glass materials of Examples 1 to 8 had a ΔE of 2.3 or higher, and a difference in color between light purple and light green was confirmed using a D65 light source and an LED light source. On the other hand, the glass materials of Comparative Examples 1 to 3 had a ΔE of less than 2.3, and were colorless regardless of the light source used, so no difference in color could be confirmed. Comparative Example 4 had a light purple hue regardless of the light source used. [Industrial applicability]

[0058] The glass material of the present invention can be suitably used in decorative items.

Claims

1. in mol%, Dy ２ O ３ 0.1 to 20%, Nd ２ O ３ 0.1 to 20%, SiO ２ + B ２ O ３ + Al ２ O ３ 0 to 80%, La ２ O ３ 0 to 90%, Nb ２ O ５ + Ta ２ O ５ + Gd ２ O ３ + ZrO ２ + TiO ２ A glass material containing 0 to 90%.

2. L when light is irradiated using an LED light source with a peak wavelength in the range of 360-500 nm and when light is irradiated using a D65 light source. ＊ a ＊ b ＊ The glass material according to claim 1, wherein the color difference ΔE in the color system is 2.3 or more.

3. Dy ２ O ３ and Nd ２ O ３ It contains, L when light is irradiated using an LED light source with a peak wavelength in the range of 360-500 nm and when light is irradiated using a D65 light source. ＊ a ＊ b ＊ A glass material having a color difference ΔE of 2.3 or more in its color system.

4. The glass material according to claim 1 or 3, wherein the content of each oxide of V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Ce, Pr, Tb, Ho, or Er is less than 2%.

5. The glass material according to claim 1 or 3, wherein the refractive index nd is 1.5 or greater.

6. An ornament comprising the glass material described in claim 1 or 3.

Images