The light gem will now emit light

src/main/java/com/minelittlepony/unicopia/spell/SpellLight.java

@@ -0,0 +1,64 @@
+package com.minelittlepony.unicopia.spell;
+
+import com.minelittlepony.util.PosHelper;
+
+import net.minecraft.block.Block;
+import net.minecraft.block.state.IBlockState;
+import net.minecraft.util.EnumFacing;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.world.EnumSkyBlock;
+import net.minecraft.world.World;
+
+public class SpellLight extends GenericSpell {
+
+    private BlockPos lastPos;
+    private ICaster<?> source;
+
+    public SpellLight() {
+        super("light", 0xF7FACB, SpellAffinity.GOOD);
+    }
+
+    @Override
+    public void onPlaced(ICaster<?> caster) {
+        this.source = caster;
+    }
+
+    @Override
+    public void setDead() {
+        super.setDead();
+
+        if (lastPos != null) {
+            source.getWorld().checkLight(lastPos);
+        }
+    }
+
+    @Override
+    public boolean update(ICaster<?> source) {
+        this.source = source;
+
+        BlockPos pos = source.getOrigin().down();
+
+        World world = source.getWorld();
+
+        if (lastPos != null && !lastPos.equals(pos)) {
+            world.checkLight(lastPos);
+        }
+
+        lastPos = pos;
+
+
+        int light = world.getLightFor(EnumSkyBlock.BLOCK, pos);
+
+        if (light < 8) {
+            world.setLightFor(EnumSkyBlock.BLOCK, pos, 8);
+            world.notifyLightSet(pos);
+            world.checkLight(pos.up());
+        }
+
+        return true;
+    }
+
+    protected void resetLight(BlockPos pos) {
+
+    }
+}

src/main/java/com/minelittlepony/unicopia/spell/SpellRegistry.java

@@ -46,7 +46,7 @@ public class SpellRegistry {
         registerSpell(SpellDarkness::new);
         registerSpell(SpellFlame::new);
         registerSpell(SpellSiphon::new);
-        registerSpell(GenericSpell.factory("light", 0xF7FACB, SpellAffinity.GOOD));
+        registerSpell(SpellLight::new);
     }
 
     @Nullable