Ep. 10: Geologists explore abandoned manganese mine and discover toxic rhodonite ballast
Aired on September 7, 2025
10
A geological team led by Yoko visits a historical manganese mine after Nagi misses the trip. They study manganese properties but are blocked by a collapsed tunnel. Searching nearby tracks, they find large quantities of rhodonite and rhodochrosite. This suggests prohibited toxic tailings were used as track ballast, possibly by a past crew for emergency repairs. The true reason for this usage remains unknown.
Episodes
- Ep. 6 · Ruri and friends locate the sapphire deposit after correcting a note error near a shrine.
- Ep. 7 · Shoko finds friends while exploring sea glass and silica color science with Ruri.
- Ep. 8 · Shoko and Ruri investigate water quality and discover orange crystals at an abandoned factory.
- Ep. 9 · Team discovers opals at dam after investigating riverbank waste and quartz sources
- Ep. 10 · Geologists explore abandoned manganese mine and discover toxic rhodonite ballast
- Ep. 11 · Ruri uses gem analysis to resolve her course selection dilemma
- Ep. 12 · Ruri discovers a crystal radio among her grandfather's belongings and attempts to build one with friends.
- Ep. 13 · Geologists visit a hot spring hotel and discover cosmic spherules in rooftop dust.