Presentation Information
[R1-11]Development of a new method for identifying Itoigawa jadeitite using thermal conductivity, magnetic susceptibility, and rebound hardness
*Takahiko OGAWARA1 (1. Fossa Magna Museum)
Keywords:
Itoigawa UNESCO Global Geopark,Jadeitite,Thermal Conductivity,Magnetic Susceptibility,Rebound Hardness
1. Introduction
Identifying jadeitite is a common challenge for tourists in Itoigawa because it closely resembles other local rocks like rhyolite, albitite, and quartz. Professional analysis is impractical for the public. This study tested if inexpensive, commercially available instruments could offer a simple solution. We investigated if measuring thermal conductivity, magnetic susceptibility, and rebound hardness could effectively distinguish jadeitite from its look-alikes.
2. Methods
We measured 120 jadeitite samples and over 370 similar rocks from our museum's collection. The following instruments, all purchased online for under 100,000 JPY, were used: Thermal Conductivity: Presidium Duo Tester II (read on a 10-level scale). Magnetic Susceptibility: Geofyzika Kappa meter KT-6. Rebound Hardness: RWBN digital concrete test hammer HD-225C.
3. Results & Discussion
Thermal conductivity proved to be a highly effective differentiator (Fig. 1). Jadeitite (mean reading: 3.44) and quartz (3.87) showed significantly higher conductivity than the other rocks, such as rhyolite (2.01) and albitite (1.71). Welch's t-test confirmed these differences were statistically significant (p < .0017), and our semi-quantitative results align with established scientific data (Robertson, 1988). This demonstrates that even a simple, inexpensive tester can reliably separate jadeitite.
In contrast, magnetic susceptibility was not a useful metric, as values were uniformly low across all rock types (Fig. 2). Rebound hardness tests failed because the samples were too small for the equipment.
In conclusion, a commercially available thermal conductivity tester is a viable, simple, and effective tool for the public to distinguish jadeitite from similar-looking rocks.
Identifying jadeitite is a common challenge for tourists in Itoigawa because it closely resembles other local rocks like rhyolite, albitite, and quartz. Professional analysis is impractical for the public. This study tested if inexpensive, commercially available instruments could offer a simple solution. We investigated if measuring thermal conductivity, magnetic susceptibility, and rebound hardness could effectively distinguish jadeitite from its look-alikes.
2. Methods
We measured 120 jadeitite samples and over 370 similar rocks from our museum's collection. The following instruments, all purchased online for under 100,000 JPY, were used: Thermal Conductivity: Presidium Duo Tester II (read on a 10-level scale). Magnetic Susceptibility: Geofyzika Kappa meter KT-6. Rebound Hardness: RWBN digital concrete test hammer HD-225C.
3. Results & Discussion
Thermal conductivity proved to be a highly effective differentiator (Fig. 1). Jadeitite (mean reading: 3.44) and quartz (3.87) showed significantly higher conductivity than the other rocks, such as rhyolite (2.01) and albitite (1.71). Welch's t-test confirmed these differences were statistically significant (p < .0017), and our semi-quantitative results align with established scientific data (Robertson, 1988). This demonstrates that even a simple, inexpensive tester can reliably separate jadeitite.
In contrast, magnetic susceptibility was not a useful metric, as values were uniformly low across all rock types (Fig. 2). Rebound hardness tests failed because the samples were too small for the equipment.
In conclusion, a commercially available thermal conductivity tester is a viable, simple, and effective tool for the public to distinguish jadeitite from similar-looking rocks.
