Amethyst: Visit the only Temple in the Dalmuhd
Aquamarine: Return to the Diaspola stage and visit
the hidden city of Ajan, nestled in between three mountain ranges a bit southeast of
the center of the map.
Diamond: Go back to the Ruined City stage. You'll
be given this stone in one of the stage's two Temples.
Emerald: Head back to the Island Avalon stage and
go to the hidden Temple in the middle of the island.
Garnet: Revisit the Slums of Zenobia stage and head
to the Temple that's northwest of your starting point.
Opal: Go back to the Lake Jannenia stage and visit
the hidden Temple east of the city of Allephal.
Pearl: This one requires a bit of work. If you've been
through a city called Somyul in the Diaspola stage, you've probably met a little girl
named Posha. If you visit that city with your Lord's unit before beating the stage,
Posha will ask you to do her a favour. To do it, head to the hidden Temple in the south;
you'll be given a Beehive. Return to Somyul and trade it for a Sentoul Demon (which you
can trade for an Undead Staff in the city of Anglem in the same stage, by the way). Now
Posha will ask you for a Ginger Cake. Wait till you beat the Organa stage, then return
to it and visit the hidden Temple on one of the eastern islands. If you've got the
Tablet of Yaru, you'll be given the Ginger Cake Posha wants. With the Cake, go all the way
back to Somyul in Diaspola.
Peridot: Return to the Muspelm stage and go to one of
Ruby: Revisit the City of Malano stage and go to
Sanbelna, a hidden city in the southeastern quadrant of the map.
Sapphire: This is the quickest one to get. Right after
you get the Tablet of Yaru in Shangrila, head to the hidden Temple in the center of the
Topaz: Go to the Ryhan Sea stage and find the hidden
temple south of your base.
Turquoise: Head to the Tundra stage and visit the
Temple on the northern central island.