Images of the issue:

 

 

 

 

 

 

 

The top and side of this item is a bit weird, it looks like not all of the pixels are rendering in 3D. The code should be fine but here it is:

 

public static void init(){
	enchanted_gem = new ItemBasic().setUnlocalizedName("enchanted_gem");
	enchanted_dust = new ItemEnchantedDust().setUnlocalizedName("enchanted_dust");	
}

public static void register(){
	GameRegistry.registerItem(enchanted_gem, "enchanted_gem");
	GameRegistry.registerItem(enchanted_dust, "enchanted_dust");
}

public static void registerRenders(){
	registerRender(enchanted_gem);
	registerRender(enchanted_dust);
}

public static void registerRender(Item item){
	Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation(Reference.MOD_ID + ":" + item.getUnlocalizedName().substring(5), "inventory"));
}

 

The item in the pics is the enchanted_gem, while enchanted_dust works perfectly fine.

Show us your item models

Here is my enchanted_gem.json:

 

{

    "parent": "builtin/generated",

    "textures": {

        "layer0": "vp:items/enchanted_gem"

    },

    "display": {

        "thirdperson": {

            "rotation": [ -90, 0, 0 ],

            "translation": [ 0, 1, -3 ],

            "scale": [ 0.55, 0.55, 0.55 ]

        },

        "firstperson": {

            "rotation": [ 0, -135, 25 ],

            "translation": [ 0, 4, 2 ],

            "scale": [ 1.7, 1.7, 1.7 ]

        }

    }

}

Try re-saving the item textures. That worked for me.

No luck

Hi

 

It's because your item texture goes right to the edge of the 16x16.

 

Have a look at minecraft vanilla textures eg stick, sword, etc.  They all leave the rightmost column and topmost row of voxels free.

 

[edit] actually the sword does go right to the edge!  Odd.  But anyway, I had this problem for one of my item icons, and leaving the rightmost + topmost free fixed it for me.

 

-TGG