Hi,
this is my first guide and I hope you read it through first before you vote it .I make this guide because in the german LOL-forum some guys wrote, that he doesn´t work as a jungler well and i show your the contrary.

First the profile of our Champ skarner: He is a predator that chases its victims mercilessly.
He needs to be very fast and unpredictable so to play him as a jungler would be my first choice.
I test this guide several games and till now i won every game (sure it depends on your mates too!)

Pro:

High dps
slows victims
Farming abillity (if you play him on a lane)
his ulti
Can gank very easily
useful in Teamfights

Contra:

His game depends on Items
squishy (lifesteal can fix it a little bit)
Weak early game
His abilities need a lot of mana

First of all if you play jungler for me the bread and butter is Smite
without smite you will loose a lot of time in the jungle!

Flash helps you to escape or initiate a gank when your ready to hunt.

Ghost is useful too but i recommend Flash because it is useful for attack and escape- with ghost you can be slowed really easy and you waste your spell if you try to escape.

I choose 16 in offense and 14 in Utilities.

As a Ganker Skarner needs to deal DMG and for get the duration of the Buffs longer he needs the points in Utility Mastery .

awareness] helps you to get the maximum xp in the jungle and with [[sunder you can get the Armor rapidly down.

-CDR (Cooldown Reduction) for spamming your abilities

Take a look at your Abilities:
Energize: This is your passive. This ability helps you to spam your skills frequently
Crystal Slash This is my spell to max it out first, because of its AOE dmg and ability to slow your oppenents Crystalline Exoskeleton this makes skarner to a perfect predator- speedbuff + shield- anything else?
Fracture could be very nice, if the scaling would be a little bit better. For me the lifeleech isn´t notable without items.
Impale This Spell is 100% fun! You can seperate the opponents Team and pull out your victim which your prefer- you can save lifes too if you care about teammates!

First i start with Crystal Slash. This is necessary for your profile jungler. with this spell you can slow your victim and harras well the lane if you need to stay their for a while.
With Crystalline Exoskeleton you got the perfect combination: movement buff for you + slow your opponent.

First i max

Crystal Slash
second Crystalline Exoskeleton
and third Fracture because the lifeleech is not the greatest.

My Skill order before a gank is from lvl. 1-5: Crystalline Exoskeleton Crystal Slash Crystal Slash Fracture= WQQE

When you got your Ulti you than: Crystalline Exoskeleton Impale Crystal Slash Crystal Slash Fracture = WRQQE

So let´s take a look at my Itembuild.
I would love to build a jungler, so i start with Cloth Armor and five heal pots.
First i build Wriggle´s Latern which is necessary for a jungler + you can place wards for you and your team!
I prefer to be the fastest Predator so i buy my Mobility Boots. Wth? Would be your first thought BUT with this movement you can gank very easy + you can follow your victims very easy.
With The Brutalizer you get CDr and DMG + Amor pen the costs aren´t very high and your dmg would be very nice till now.
Philosopher's Stone helps you to recover your Life + Mana which you use a lot in a litte short period of time. The secound thought about is - you can combine Impale with Shurelya's Battlesong (Uoesn´t work with Flash for example).
The Hextech Gunblade gives you AP + DMG so it explans itselfs.
With [Banshee's Veil] do you have some magicresistance + Life and Mana.

This itembuild is not ready. i´m thinking about Sheen + Trinity Force....

My Joungleroute is nothing special i guess.
*I do not create this map- i found it on google and i found it very helpful to explain my route*

Let somebody pull you the Blue Golem and after you kill him visit the wolves- start using your first Healpot after you get hit by the big boy.
After Blue you go to the whitches and use your Smite at the big one- after you finish them you are LVL 3.
Than go to the two Golems and at least you can make the Red Buff. When you use your Pots right, the five will be sufficent for the whole jungle!
After the jungle you are LVL 4 and it is time for your Gank!

Ganking with Skarner is very funny! BUT: It is important to communicate with your Teammates!
Ping early and ask everytime if your mate is ready!
If you gank mid so start with Crystalline Exoskeleton > than Flash and than Crystal Slash

So at least this guide is not finish and i like to finish it with your help! So pls tell me your thoughts and ideas which you have with Skarner.
I hope this guide helps you and shows that Skarner is a good Jungler.
I will update this Guide daily.