No enhancing with anything other than wood/metal/leather and only according to which applies to whatever your enhancing.

Wood is the only one which adds properties/modifies damage distribution/adds resists, metal and leather just add resists to armor, and metal only modifies damage distribution.

You can use any of the jewels from mining/chopping/fishing to craft jewelry. The web is woefully underpopulated with info on this, but I do know that crafting bracelets (possibly ring) with an ecru citrine can give you 75% enhance pots.

For crafting from runics ben, yes, you can enhance a runic crafted item after it is crafted. But why would you? You have a HUGE chance of failure then. It is best to craft it from the material you want to enhance it with.

ecru citrine ring can give you 75% enhance pots Its a ring

Oak by Weapons :
40 Luck
Damage Increase 5%

Oak by Armor Parts :
40 Luck
Physical Resist 3%
Fire Resist 3%
Posion Resist 2%
Energy Resist 3% (11 Resists Total)

Oak by Shields :
All Resists +1%

Ash by Weapons :
Swing Speed Increase 10%
Lower Requirenments 20%

Ash by Armor Parts :
Lower Requirements 20%
Physical Resist 2%
Cold Resist 4%
Poison Resist 1%
Energy Resist 6% (13 Resists Total)

Ash by Shields :
Energy Resist 3%
Lower Requirements 20%

Yew by Weapons :
Hit Chance Increase 5%
Damage Increase 10%

Yew by Armor Parts :
Hit Point Regeneration +1
Physical Resist 6%
Fire Resist 3%
Cold Resist 3%
Energy Resist 3% (15 Resists Total)

Yew by Shields :
Hit Point Regeneration 1
Physical Resist 3%

Heartwood by Weapons :
Only one of the following Random abilitys :
Spell Channeling -1
Swing Speed Increase 10%
Damage Increase 10%
Hit Chance Increase 5%
Luck 40
Hit Life Leech 10%
Lower Requirements 20%
Weight -2

Heartwood by Armor Parts :
Only one of the following Random abilitys :
Spell Channeling -1
Swing Speed Increase 10%
Damage Increase 10%
Hit Chance Increase 5%
Luck 40
Hit Life Leech 10%
Lower Requirements 20%
Weight -2
Physical Resist 2%
Fire Resist 3%
Cold Resist 2%
Poison Resist 7%
Energy Resist 2% (16 Resists Total)

Heartwood by Shields :
Only one of the following Random abilitys :
Dexterity +2
Strengh +2
Spell Channeling -1
Cold Resist 3%
Physical Resist 5%
Reflect Physical Damage 5%

Bloodwood by Weapons :
Hit Life Leech 16% (it add's not up, if your Weapon has already Hit Life Leech)
Hit Point Regeneration +2

Bloodwood by Armor Parts :
Hit Point Regeneration +2
Physcial Resist 3%
Fire Resist 8%
Cold Resist 1%
Poison Resist 3%
Energy Resist 3% (18 Resists Total)

Bloodwood by Shields :
Hit Point Regeneration +2
Luck 40
Fire Resist 3%

Frostwood by Weapons :
Damage Increase 12%
Physical Damage 60%
Cold Damage 40%

Frostwood by Armor Parts :
Physcial Resist 2%
Fire Resist 1%
Cold Resist 8%
Poison Resist 3%
Energy Resist 4% (18 Resists Total)

Frostwood by Shields :
Spell Channeling -1
Cold Resist 3%