The girl on the left is Nagi Arato and the one on the right is Ruri Tanigawa. Both of them are in their swimsuits.

These girls are enjoying themselves after looking for rare gemstones and rocks during their research. Just appreciate their hard work for ma...

This OP theme song is called, "Hikaru no Sumida" by Rei Yasuda and I hope you can enjoy rock and mineral collecting and analyzing ...