Put a unique item and the required runes/gems in the cube to add stats to it.  Be careful and make sure that you don't make the level requirement go too high!

WEAPONS

ruby, 5-6 fire damage per level
chipped ruby x3, 5-6 fire damage, +1 level
flawed ruby x3, 10-12 fire damage, +2 levels
ruby x3, 15-18 fire damage, +3 levels
flawless ruby x3, 20-24 fire damage, +4 levels
perfect ruby x3, 25-30 fire damage, +5 levels

topaz, 1-10 lightning damage per level
chipped topaz x3, 1-10 light damage, +1 level
flawed topaz x3, 2-20 light damage, +2 levels
topaz x3, 3-30 light damage, +3 levels
flawless topaz x3, 4-40 light damage, +4 levels
perfect topaz x3, 5-50 light damage, +5 levels

sapphire, 3-5 cold damage per level
chipped sapphire x3, 3-5 cold damage, +1 level
flawed sapphire x3, 6-10 cold damage, +1 level
sapphire x3, 9-15 cold damage, +1 level
flawless sapphire x3, 12-20 cold damage, +1 level
perfect sapphire x3, 15-25 cold damage, +1 level

emerald, 10 poison damage per level, 2 second duration.
chipped emerald x3, 10 poison damage, +1 level
flawed emerald x3, 20 poison damage, +2 levels
emerald x3, 30 poison damage, +3 levels
flawless emerald x3, 40 poison damage, +4 levels
perfect emerald x3, 50 poison damage, +5 levels

amethyst, 50 AR per level
chipped amethyst x3, 50 ar, +1 level
flawed amethyst x3, 100 ar, +2 levels
amethyst x3, 150 ar, +3 levels
flawless amethyst x3, 200 ar, +4 levels
perfect amethyst x3, 250 ar, +5 levels

diamond, 7% damage per level
chipped diamond x3, 7% ed, +1 level
flawed diamond x3, 14% ed, +2 levels
diamond x3, 21% ed, +3 levels
flawless diamond x3, 28% ed, +4 levels
perfect diamond x3, 35% ed, +5 levels

skull, 1/3 dual leech per level
chipped skull x3, 1% dual leech, +3 levels
flawed skull x3, 2% dual leech, +6 levels
skull x3, 3% dual leech, +9 levels
flawless skull x3, 4% dual leech, +12 levels
perfect skull x3, 5% dual leech, +15 levels

el x2, +2 to light radius, +1 level
eld x2, 70% damage to undead, 100 ar to undead, +10 levels
tir x3, +2 mana per kill, +3 levels
nef x4, knockback, +6 levels
eth x3, -10% enemy defence, +8 levels
ith x3, +10 max damage, +4 levels
tal x4, +12% poison damage, -5% enemy poison resist, +10 levels
ral x4, +12% fire damage, -5% enemy fire resist, +10 levels
ort x4, +12% lightning damage, -5% enemy light resist, +10 levels
thul x4, +12% cold damage, -5% enemy cold resist, +10 levels
amn x3, 10% life leech, +15 levels
sol x3, +8 min damage, +4 levels
shael x3, 20% ias, +10 levels
dol x3, +5 replenish life, +7 levels
hel x3, -10% requirements, +5 levels
io x3, +10 vitality, +5 levels
lum x3, +10 energy, +5 levels
ko x3, +10 dexterity, +5 levels
fal x3, +10 strength, +5 levels
lem x2, 50% gold find, +4 levels
pul x2, 70% damage to demons, 100 ar to demons, +10 levels
um x2, 10% open wounds, +5 levels
mal x3, prevent monster heal, +8 levels
ist x2, 75% magic find, +9 levels
gul x2, 20% attack rating, +15 levels
vex x3, 10% mana leech, +15 levels
ohm x2, 315% ed, +45 levels
lo x2, 10% deadly strike, +10 levels
sur x2, hit blinds target, +15 levels
ber x2, 20% crushing blow, +16 levels
jah x2, ignore targets defece, +30 levels
cham x2, hit freezes target, +30 levels
zod x2, indestructable, ethereal, +30 levels

STAVES

Ral, Perfect Ruby, +1 to fire mastery(sorceress only), +3 levels
Ort, Perfect Topaz, +1 to lightning mastery(sorceress only), +3 levels
Thul, Perfect Sapphire, +1 to cold mastery(sorceress only), +3 levels
Shael x2, Perfect Diamond, 10% faster cast rate, +5 levels
Hel, Perfect Skull, +1 skill levels, +10 levels
Eth x2, Tir x2, 25% mana regen, +4 levels

THROWING

Dol, Perfect Skull, replenish quantity, +7 levels

KATARS

Shael, Perfect Skull, +1 assassin skills, +12 levels

ORBS

Lum, Perfect Sapphire, +1 sorceress skills, +12 levels

ARMOR

ruby 4% fire resist per level
chipped ruby x3, 4% fire resist, +1 level
flawed ruby x3, 8% fire resist, +2 levels
ruby x3, 12% fire resist, +3 levels
flawless ruby x3, 16% fire resist, +4 levels
perfect ruby x3, 20% fire resist, +5 levels

topaz 4% light resist per level
chipped topaz x3, 4% light resist, +1 level
flawed topaz x3, 8% light resist, +2 levels
topaz x3, 12% light resist, +3 levels
flawless topaz x3, 16% light resist, +4 levels
perfect topaz x3, 20% light resist, +5 levels

sapphire 4% cold resist per level
chipped sapphire x3, 4% cold resist, +1 level
flawed sapphire x3, 8% cold resist, +2 levels
sapphire x3, 12% cold resist, +3 levels
flawless sapphire x3, 16% cold resist, +4 levels
perfect sapphire x3, 20% cold resist, +5 levels

emerald 4% poison resist per level
chipped emerald x3, 4% poison resist, +1 level
flawed emerald x3, 8% poison resist, +2 levels
emerald x3, 12% poison resist, +3 levels
flawless emerald x3, 16% poison resist, +4 levels
perfect emerald x3, 20% poison resist, +5 levels

amethyst 4% defence per level
chipped amethyst x3, 4% defence, +1 level
flawed amethyst x3, 8% defence, +2 levels
amethyst x3, 12% defence, +3 levels
flawless amethyst x3, 16% defence, +4 levels
perfect amethyst x3, 20% defence, +5 levels

diamond 1% all resist per level
chipped diamond x3, 1% all resist, +1 level
flawed diamond x3, 2% all resist, +2 levels
diamond x3, 3% all resist, +3 levels
flawless diamond x3, 4% all resist, +4 levels
perfect diamond x3, 5% all resist, +5 levels

skull +1 replenish life/4% mana regen per 2 levels
chipped skull x3, +1 replenish, 4% mana regen, +2 levels
flawed skull x3, +2 replenish, 8% mana regen, +4 levels
skull x3, +3 replenish, 12% mana regen, +6 levels
flawless skull x3, +4 replenish, 16% mana regen, +8 levels
perfect skull x3, +5 replenish, 20% mana regen, +10 levels

el x2, +2 to light radius, +1 level
eld x3, 25% slower stamina drain, +4 levels
tir x3, +2 mana per kill, +3 levels
nef x4, +100 defence vs missiles, +5 levels
eth x3, 20% mana regen, +5 levels
ith x3, 10% damage to mana, +6 levels
tal x4, 40% poison resist, +10 levels
ral x4, 40% fire resist, +10 levels
ort x4, 40% light resist, +10 levels
thul x4, 40% cold resist, +10 levels
amn x3, attacker takes damage of 30, +4 levels
sol x3, damage reduced by 10, +4 levels
shael x2, 10% hit recovery, +10 levels
dol x2, +5 replenish life, +5 levels
hel x2, -10% requirements, +5 levels
io x3, +10 vitality, +7 levels
lum x3, +10 energy, +7 levels
ko x3, +10 dextrerity, +7 levels
fal x3, +10 strength, +7 levels
lem x2, 50% gold find, +4 levels
pul x2, 80% defence, +20 levels
um x2, 15% all resist, +15 levels
mal x2, magic damage reduced by 10, +4 levels
ist x2, 75% magic find, +9 levels
gul x2, +2% to max poison resist, +25 levels
vex x2, +2% to max fire resist, +25 levels
ohm x2, +2% to max cold resist, +25 levels
lo x2, +2% to max light resist, +25 levels
sur x2, 5% max mana, +15 levels
ber x2, 5% damage reduction, 15 levels
jah x2, 5% max life, +30 levels
cham x2, can't be frozen, +30 levels
zod x2, ethereal, indestructable, +30 levels

SHIELDS

eld x4, 5% block rate, +8 levels
shael x3, 5% faster block, +8 levels

BOOTS

any gem x 8, 10% faster run/walk, +5 levels
shael x3, 40% faster run/walk, +20 levels
eld x4, +50 to stamina, +2 levels

GLOVES

shael x4, 10% increaced attack speed, +10 levels

SHRUNKEN HEADS

perfect skull, tal, +1 necromancer skills, +12 levels

BARBARIAN HELMETS

perfect ruby, ral, +1 barbarian skills, +12 levels

DRUID PELTS

perfect sapphire, thul, +1 druid skills, +12 levels

PALADIN SHIELDS

perfect diamond, ort, +1 paladin skills, +12 levels