NoSuchFieldError: materialPureifiedCertusQuartzCrystal (AE2 & Thaumic Energistics)

What the log looks like

cpw\.mods\.fml\.common\.LoaderException: java\.lang\.NoSuchFieldError: materialPureifiedCertusQuartzCrystal
java\.lang\.NoSuchFieldError: materialPureifiedCertusQuartzCrystal

How to fix it

1. Open your Minecraft `mods` folder and locate the `.jar` files for Applied Energistics 2 and Thaumic Energistics.
2. Download the latest stable 1.7.10 version of Applied Energistics 2 (such as rv3) from CurseForge.
3. Download the latest 1.7.10 version of Thaumic Energistics—along with updates for any other AE2 addons you use—to ensure they match the updated AE2 API.
4. Delete the old `.jar` files for both mods from your `mods` folder, drop in the newly downloaded versions, and launch the game.

Check your own log