The highly anticipated first season of the mineralogy-themed anime Ruri Rocks, also known as Ruri no Hōseki or Introduction to Mineralogy, officially concluded its broadcast on September 28, 2025, leaving viewers with a heartfelt exploration of scientific curiosity and intergenerational connection. While Episode 12 initially presented many hallmarks of a season finale, an unexpected thirteenth episode ultimately served as the true capstone to Ruri Tanigawa’s journey into the world of rocks and gems.
Episode 12: A Look Back Through Time with a Crystal Radio
Episode 12, which aired on September 22, 2025, delved into a deeply personal arc for protagonist Ruri. The installment saw her discovering a connection to her deceased grandfather through his old crystal radio hobby. This revelation offered a tangible link to her past, highlighting themes of communication across generations and how accumulated knowledge can foster posthumous connections.
The episode centered on Ruri’s efforts, alongside her friends, to recreate her grandfather’s crystal radio, using various rocks as detectors. This pursuit reinforced the show’s overarching message about the growth of young scientists and how studying one subject can lead to a branching array of additional interests and hobbies. While the device initially struggled to work with natural minerals, the eventual success, even with a modern germanium diode, solidified Ruri’s understanding and appreciation for the scientific process and her family’s history. The episode’s narrative structure, including a climactic deployment of the theme song and a strong thematic resolution, led many to perceive it as the season’s definitive ending.
The Unforeseen Episode 13: A True Season Wrap-Up
Despite Episode 12’s strong concluding feel, the narrative momentum of Ruri Rocks continued into a thirteenth episode, officially ending the season on September 28, 2025. A post-credits scene in Episode 12 subtly hinted at this continuation, showing character Imari winning a raffle, thereby setting up further events. Although specific plot details for Episode 13 are not yet widely detailed, its existence ensured a complete run of 13 episodes for the season. This extension likely provided a more thorough resolution or a gentle segue into future possibilities for Ruri and her friends.
Ruri’s Transformative Journey
Throughout its run, Ruri Rocks has captivated audiences with its unique blend of slice-of-life charm and educational insights into mineralogy. Ruri Tanigawa’s initial fascination with “shiny things” evolved into a genuine appreciation for the science and natural beauty of the Earth. Under the guidance of mineralogy graduate student Nagi Arato, Ruri explored various minerals like quartz, garnets, pyrite, gold, and fluorite, learning about their formation, properties, and collection methods.
The series consistently showcased Ruri’s growth, from a curious high schooler to a budding earth scientist, emphasizing the importance of observation, research, and perseverance in scientific discovery. Each episode offered “Cool Rock Facts™” and demonstrated how seemingly dull stones could hide brilliant colors and complex histories, serving as a gentle metaphor for hidden beauty and layered discoveries.
Reflecting on the First Season and Future Prospects
The first season of Ruri Rocks, produced by Studio Bind and directed by Shingo Fujii, has been praised for its stunning visuals, relatable characters, and meaningful narrative. It successfully translated Keiichirō Shibuya’s manga into an engaging animated experience, fostering interest in geology and coming-of-age tales.
While there has been no official announcement regarding a second season, the themes of continuous learning and exploration prevalent in the finale, combined with the unexpected continuation into a 13th episode, leave the door open for Ruri’s adventures in mineralogy to continue. Fans eagerly await any news regarding the future of this unique and heartwarming series.
