Sor Crystals are vital items when it comes to forging legendaries. In order to successfully construct a Sor Crystal, you will need Onrane and Sor Fragments.

Gathering Sor Fragments
1 to 3 Sor Fragments drop from most bosses that you will run across such as events, dungeon bosses, and Oryx. You obtain the most from Raids, and Alerts. 50 of these Sor Fragments can be used to construct a Regular Sor Crystal. You can do this by going to your tabs and clicking the diamond symbol as shown below.


Then, go to your Sor Crystal Construct button. You should double check if you have enough Sor Fragments ready to build your crystal by hovering over the Sor Crystal picture.


Once you have enough Sor Fragments, click the Construct button and it will send a Sor Crystal to your Gift Chest!

Sor Crystal Ascension

Now that you have your Sor Crystal, you can now use Onrane to upgrade it to a Legendary Sor Crystal. Double-click or shift-click the Sor Crystal as if you were using it. Then, a prompt will show and ask you if you ready to ascend your crystal for 20 onrane. If you have enough Onrane, it will change your Sor Crystal to a Legendary Sor Crystal which can be used to forge legendaries.