Hello. This is my Malphite Build. I feel that with these different masteries, runes and items you can be very tanky and consume lots of damage from just malphite's passive, which gives him a sheild that asorbs 10% of his health and banshee's veil, which denies the first spell casted on malphite.
With lots of armour from the items you can tank a lot of damage and deals massive damage from his E ability. With 344.4 armour plus the armour from your W spell you reduce 82% physical damage!
Now when you play Malphite, your job is to initiate the team fights and to take all the damage. To initiate my spell combo is to use the R spell or his ultimate to knock everyone up, use your W spell to gain armour and deal extra damage on your E spell, use the E spell while they are knocked up, use Randuin's Omen active to slow them, and lastley use the Q spell on they're squishiest champion to slow them down so your team can get the first kill in the team fight and to get that "edge" for later in the team fight so you can get the ace and push into they're base.

For ruins I like to take armour marks instead of health marks mainly because armour helps you in team fights and for your E spell. Plus you get enough health from the items. For seal's I take vitality becuase it just gives so much health late that can really help for survival and for your passive. For glyphs, I choose magic resist because you also need to be able to take damage from those casters. Lastley, for quints I choose flat health but you can also choose amrour.

For masteries I like to take a 0/21/9 mainly because all tanks should max out in the defensive tree for maximum effectiveness. In the defensive tree I take increased magic resist and armour for more survivability, increased health regen so I can stay longer in lane, 2% dodge and a movement boost so I can chase and get away better, reduced physical damage, flat health and 4% reduced damage.
In utility I take increased mana and health regen to stay in lane faster, increased teleport, increased exp. so I level up faster and increased buff duration because I find it's very important to get blue so you can keep maximum mana!

For items, I choose a Regrowth Pendant and a health potion so I can stay in lane a lot longer. Once I'm back in the base I immediately rush Philosopher's Stone, Boots of Speed and Heart of Gold if I have the money. After Heart of Gold I usually Take A Giant Belt followed by Sunfire Cape. Immediately after Sunfire Cape I rush Warden's Mail and then a Randuin's Omen. To finish off the six items I take Shurelya's Reverie and Thornmail, but if you find that you still use too much mana and not enough armour sell the Shurelya's Reverie and take a Frozen Heart instead.

For skills I take the common route:

Max out your Q spell first because it's very useful for early/late game harrasing, does lots of damage and great for chasing and getting away.

Take one point in your E spell at level 2 and then level it up whenever you can't level up your Q. Your E does great damage with lots of armour and helps against champions with lots of attack speed.

Take one point in your W spell at level 4 the burst damage on minions and for that extra damage and armour for early game kills. Then max it out last.

And of course level up your ultimate whenever you can because it's great for team fights, single target fights, for chasing and for getting away.

For spells I choose Flash and Teleport because Flash helps for chasing and getting away when that target just gets out of range for your Q spell and Teleport allows you to go back and immediately come back before the enemy's on your turret. Teleport can also be effective when your team has a team fight and your not around or to escape and gank/fight if your going to die. These are the reasons why I dont choose the other spells:

Heal: I think it would be effective in team fights but you already have a lot of health and Flash/Teleport are more effective.

Clarity: Good for early game but once you get Philosper's Stone and pick up Blue buff every now and then you'll be fine.

Ghost: Great for chasing and getting away but that's what your Q spell is for.

Clairvoyence: A tank/bruiser should not get it, your support should.

Exhaust: Same as Ghost, good for chasing and getting away but that's what your Q spell is for.

Cleanse: Good for escaping team fights but I believe you should be the one saving your teamates not running away.

Revive: This spell is for noobs.

Smite: This is not a jungling build.

Fortify: Useful but not as useful as Flash and Teleport.

Ignite: Good for getting kills but isn't as useful mid/late game and in team fights.

Rally: Does not help out Malphite.