Mining (Harvest Moon: Magical Melody)
From Harvest Moon | Rune Factory Wiki
To go mining all you need is a hammer. The mine is behind rions farm and consists of 100 levels. To mine just smash crystals or stones and pick up what they drop behind. You have to be careful because sometimes gasses will appear and have different effects on you. Standing on cracks on the floor will make you randomly go up or down a level, skipping levels altogether sometimes. Whenever you want to get out just walk to the stairs. Some items can only be found by plowing the ground.
There is also another mine that opens up in winter on the lake when it freezes over.
Once you reach level 100 in the mine, Tim will reward you with a power berry and you find some ruins of some sort. Once you reach level 100 in the winter mine, you reach and underground lake and if you use your fishing rod, you might catch a legendary fish!
Here is a list of the different gems and objects you can find:
Garbage Stone - useless and sells for only 1g.
Moonstone - used to activate festivals and make jewelry. Sells for 100g.
Copper - used to upgrade tools. Sells for 50g.
Silver - used to upgrade tools. Sells for 80g.
Gold - used to upgrade tools. Sells for 120g.
Rare Metal - used to upgrade tools to the highest point. Sells for 300g.
Amethyst - pretty gem with which you can make jewelry. Sells for 440g.
Aquamarine - pretty gem with which you can make jewelry. Sells for 450g.
Topaz - pretty gem with which you can make jewelry. Sells for 480g.
Sapphire - pretty gem with which you can make jewelry. Sells for 500g.
Emerald - pretty gem with which you can make jewelry. Sells for 650g.
Ruby - pretty gem with which you can make jewelry. Sells for 700g.
Limestone - a rock that can be used to activate a secret event not yet known (possibly a new villager or a Happiness Tone), you do this by shipping it. Sells for 20g.
Diamond - pretty gem with which you can make jewelry. Sells for 1,000g.
Clay - normally found on the first floor by plowing, ship it and ogihara will move in. He can use it to create objects. Sells for 20g.
Pontata Root - a gift enjoyed by some villagers.
There are also gases you will find while digging;
Orange Gas - temporary paralysis.
Pink Gas - restores energy.
Purple Gas - messes up your controls.
Red Gas - limits your sight.
Yellow Gas - speeds up your character.
The winter mine has a certain pattern;
Level 5: All are Moonstones.
Level 10: Dead end, only way out is out of the mine.
Level 15: All are Amethysts.
Level 20: All are Aquamarines.
Level 25: All are Topaz.
Level 30: All are Sapphires.
Level 35: All are Emeralds.
Level 40: All are Rubies.
Level 45: All are Crystals are Limestone and all rocks are Garbage Stone.
Level 50: All are Diamonds.
Credit to: Arcaneja, Cher and LordShtzu