TERAH-R-01 Origin: China Grade: AA Dimensions: Approximately 25-40mm Weight: Approximately 20-30g Origin: China Grade: AA = very high Tumbled Terahertz stone from China, 25-40mm. Sold individually. Shapes and colors may vary from one stone to another. Terahertz is described as an "artificial wonder" originating from Japan. It is obtained by combining silicon, extracted from quartz, with titanium, causing this stone to emit a vibration in the terahertz spectrum. This artificial gemstone was discovered by Japanese scientists 10 years ago, having a terahertz frequency located between that of far-infrared light on the electromagnetic spectrum and that of microwaves.