[5.0] Malphite Guide - Geodude

You want to build items that grant Armor, since your W Thunderclap and E Ground Slam scale with armor. The more armor, the more armor and damage you get.

Starting Item:

• Ruby Crystal is your best choice into most matchups, since you want to rush boots and the HP will help you survive any types of dmg while amror would only help vs AD.
• Cloth Armor might be good into very specific matchups like tryndamere who only deals physical damage, but your W Thunderclap will already grant you a lot of Armor, so HP is probably the best.
• Amplifying Tome is you want to poke down the squishy Teemo early even harder, but it is really not needed and just makes you squishier.

Legendary Items:

• [Iceborne Gauntlet]
  will proc everytime you use your W Thunderclap and the damage of this item also scales with armor. That is why it should be almost always on your build as first or second item.
  
  
• [Sunrife Aegis]
  just grants you mor HP, waveclear and quite a lot of damag to champions, too. The problem with stacking a lot of armor is, that you won't have as much HP, that's why Sunfire is a good item to balance out this weakness a bit.
  
  
• Thornmail
  is another very good item on malphite, since  the damage it deals scales off of your armor and HP, while also granting you some HP and a ton of armor.
  
  
• Frozen Heart
  is another high armor item, which you should only build if the enemy team has a lot of attack speed. Your E Ground Slam already slows the attack speed of the enemy a lot, so this is only really good, if they have multiple auto attackers you want to slow down in team fights.
  
  
• Force of Nature or [Kaenic Rookern]
  can help a ton vs magic dmg, since most matches won't be just AD-Damage enemies. Keep an eye out for who is fed on the enemy team, and if you really need another amror item, or should go for MR, so you don't get oneshot by veigar or so.
  
  
• Amaranth Twinguard
  is another high armor item which will increase your damage output by a lot and also helps you vs magic damage.
  
  
• Randuin's Omen
  is a very good pick, if the enemy has a lot of critical hits going on or if you just need more HP and Armor. Look at their items and champions. Typically very good vs Yasuo , Yone , Jinx , Zeri , Caitlyn , Jhin , Tryndamere etc.
  
  
• Divine Sunderer
  is a very niche item, but it can be very strong vs high HP targets, like Sion or Dr. Mundo . Keep in Mind that Spellblade Items don't stack their bonus damage, so you should not build [Iceborne Gauntlet] and Divine Sunderer together.