While shopping, high school student Ruri Tanigawa is captivated by a crystal necklace. Due to its high price, she can only dream of owning one—until her mother tells her about a mountainous area where Ruri's grandfather used to discover numerous minerals. As she makes her way to the location in the hope of finding materials to make her own accessories, Ruri meets Nagi Arato, a graduate student, who gladly shows her the way.

Soon, Ruri is left smitten when they arrive at an enormous quartz formation. More motivated than ever, she convinces Nagi to teach her more about mineralogy. With each new discovery and Nagi's lessons deepening her love, Ruri learns that there is more to minerals than just their price.