#loader gregtech
import mods.gregtech.material.MaterialStack;
import mods.gregtech.material.Material;
import mods.gregtech.material.MaterialRegistry;
import mods.gregtech.StoneType;
import mods.gregtech.material.MaterialBuilder;
import mods.gregtech.ore.OrePrefix;
import mods.gregtech.ore.IOreRecipeHandler;
import mods.gregtech.recipe.Utils;
import mods.gregtech.material.IMaterialPredicate;
import mods.gregtech.MaterialFlag;
import mods.gregtech.MaterialFlagBuilder;



global eggFlag = MaterialFlagBuilder.create("create_egg")
   .requireDust()
   .requireFlag("create_egg")
   .build();

val eggMaterial as OrePrefix = OrePrefix.registerOrePrefix("egg", 1, "egg", 2);
eggMaterial.setGenerationPredicate(function(mat as Material) as bool {
    return mat.hasDust();
} as IMaterialPredicate);
eggMaterial.createMaterialItem();

<material:copper>.addFlags("create_egg");


// using curved plate prefix from above as example
eggMaterial.setGenerationPredicate(function(mat as Material) as bool {
    return mat.hasFlag("create_egg");
} as IMaterialPredicate);