In the fascinating world of mineralogy, every rock tells a story, and Ruri Rocks episode 9, titled “Time Capsule of 1.9 Million Tons,” delivered a narrative rich with discovery and geological wonder. This installment continued the journey of high school student Ruri Tanigawa and her mentor, graduate student Nagi Arato, alongside their friends, as they delved into the unexpected treasures unearthed by nature’s forces. Airing on August 31, 2025, in Japan, this episode was a captivating blend of scientific exploration and the endearing slice-of-life charm that fans have come to expect from the series.
Episode 9: Plot and Key Discoveries
Following directly from the events of the previous episode, where Ruri and Shouko Seto were working on a school project concerning water pollutants and briefly encountered, then lost, a peculiar orange rock (identified as zincite from a factory chimney), episode 9 saw the protagonists embark on a new mineral hunt. This time, their quest was influenced by a record-breaking heavy rainstorm that prompted the nearby dam to open its gates, leading to significant changes in the riverbed.
Instead of the placer gold they initially sought, Ruri and Shouko made a far more astonishing discovery: a substantial deposit of opals, revealed after having been hidden by the dam for over two decades. This unexpected find underscored the episode’s central theme—that geological wonders are often unveiled by the powerful, transformative hand of nature, highlighting how water movement can shift and expose long-concealed mineral veins. Nagi Arato and Youko Imari joined the duo, lending their expertise and camaraderie to the exciting expedition.
Production Highlights and Visual Storytelling
Studio Bind, the animation studio behind Ruri Rocks, garnered particular praise for its exquisite craftsmanship in episode 9. The animation captured the dynamic interplay of weather and environment, with hard cuts effectively conveying the impact of the heavy rain and the vastness of the dam. The episode masterfully depicted the sparkling outdoors, the changing weather, and the scale of the dam, impressing viewers with its attention to detail and ability to make the natural world feel both grand and intimately connected to the characters’ discoveries.
Beyond the geological pursuits, the episode also featured character-focused moments, including a “Nagi fashion show”. This sequence, while seemingly a departure from the mineral hunt, showcased the animators’ ability to blend engaging character interactions with the core themes, offering a glimpse into the personalities and relationships within the group. The backgrounds, from the empty library where Shouko and Ruri studied to Nagi and Imari’s lab, were meticulously rendered, using light and shadow to enhance the emotional tone and display the setting’s atmosphere.
Release and Streaming Information
“Ruri Rocks” episode 9, “Time Capsule of 1.9 Million Tons,” first aired on Sunday, August 31, 2025, at 9:30 PM JST on Tokyo MX and other local Japanese television networks. For international audiences, the episode became available to stream globally on Crunchyroll, with English subtitles. Viewers in Southeast Asia also had access to the episode via Aniplus Asia. The release schedule for Crunchyroll varied by time zone, with the episode typically becoming available early Sunday morning in regions like Pacific Daylight Time (5:30 AM), Eastern Daylight Time (8:30 AM), and British Summer Time (1:30 PM).
This episode is part of a 13-episode season for Ruri Rocks, which began airing in July 2025. The series continues to offer a unique blend of casual slice-of-life narrative and engaging geological adventures, making each episode a refreshing exploration of Earth’s natural wonders through the eyes of its passionate characters.
