180 JOURNAL OF COSMETIC SCIENCE 35 3O %' 25 ._ rr 20 -• 15 •10 -- 5 0 0.25 1 3 7 Contents(%) Figure 5. The increasing ratio of emissivity of the O/W emulsion containing the tourmaline powder. The y-axis is the increasing ratio (percentile) and the x-axis is the contents of the tourmaline powder. These results of saturation at 1% content were confirmed from the results of emissivity estimation. The emissivity results are shown in Figure 5 for the tourmaline powder and Figure 6 for the jade powder. The emissivity was saturated at 1% of the contents of both of the jewelry powders. From the results of emissivity and emission energy estimation, the content of each powder was determined to be 1% of the total amount as a cosmetic ingredient. The sample creams were prepared, and the contents of each powder were fixed at 1% (w/w). The skin temperatures of all the subjects were raised about one degree, as shown in Table II. The thermographic analysis data are shown in Figure 7 for the tourmaline 1% cream (T-cream), and Figure 8 for the jade 1% cream (J-cream). The T-cream and 35 30 'S' 25 ._ rr 20 halo 5 o 0.25 1 3 7 Contents(%) Figure 6. The increasing ratio of emissivity of the O/W emulsion containing the jade powder. The y-axis is the increasing ratio (percentile) and the x-axis is the contents of the jade powder.

JEWELRY POWDERS AND FAR-INFRARED RAYS 181 Table II. Temperature Elevation Induced by Jewelry Powders Before application After application Right Left AT, Right Left AT 2 T-cream TT,mean J-cream Tj,mean 31.2 31.3 0.1 31.3 32.5 1.2 32.3 32.4 0.1 32.6 33.6 1.0 32.0 32.0 0 32.9 33.8 0.9 32.5 32.5 0 32.8 33.7 0.9 33.5 33.3 0.2 32.9 33.7 0.8 0.08 _+ 0.08 1.0 _+ 0.2 29.7 30.0 0.3 31.0 32.3 1.3 33.6 33.8 0.2 33.3 34.4 1.1 31.4 31.4 0 31.9 33.0 1.1 32.2 32.3 0.1 32.1 32.9 0.8 32.2 32.3 0.1 33.1 33.9 0.8 0.1 -+ 0.1 1.0 _+ 0.2 ATe: skin temperature differences on the subject's face before application. AT2: skin temperature differences on the subject's face after application. TT ..... : mean skin temperature differences in T-cream. T3 .....: mean skin temperature differences in J-cream. the J-cream were applied to the left side of the subject's face and the control cream was applied to the right side. Representative thermographs are shown. The control cream was applied to the right side and the powder-containing cream was applied to the left side of each subject's face. The skin temperature elevation rate was different in each subject, and some subjects showed rather late temperature elevation, while others showed very fast temperature elevation. These results might be induced by the sensi- tivity of each subject to far-infrared rays. Right after the treatment, the skin temperature was cooled down by the water evaporation and then increased. The skin temperature elevation rate was mainly due to blood circulation in capillary blood vessels, and far infrared rays might be helpful in accelerating the blood circulation below the skin layer. As shown in Figures 7 and 8, before the treatment the temperature of both side of a subject's face was almost same, and the temperature differences of both sides were not significant and did not exceed + 0.3 ø for all the subjects in controlled measurement conditions. CONCLUSION In this study it was demonstrated that the jade and the tourmaline powders radiated far-infrared rays and that the intensity of the wave energy was proportional to the contents of the jewelry powders. As a cosmetic ingredient, the optimum content of the jewelry powders was 1% (w/w). After the O/W emulsion formulations containing the jewelry powders were applied to the face, the radiation energy from the jewelry powders elevated the skin temperature. It is thought that the measured skin temperature eleva- tion might be the result of the acceleration of percutaneous blood circulation. Depending on the subject's sensitivity to far-infrared rays, the skin temperature elevation varied