The three tortoise sisters; Olga, Masha, and Irina; are giant tortoises and points of interest that act as farms for wood or certain minerals.
Stella can "plant" something in each of the three nodes on the back of each of the tortoises. If a log was planted then a tree of the respective type will grow, and if a mineral was planted then a rock of the respective type will grow. After planting items in the nodes, Stella can talk with the tortoise to confirm she is done, after which the tortoise will disappear underwater and reappear some time later when the trees or rocks are finished growing.
Plantable Materials[]
Minerals:
Ores:
Wood:
Note: 
Pulsar Ore and Comet rock cannot be planted and must be acquired from its event.
Trivia[]
- The tortoise sisters are a reference to the Three Sisters, a Russian play written in 1900 by Anton Chekhov.