Trying to get the id from a lapis lazuli dye.
All dyes are metadata values of Items.dye (i.e. they share an ID).
Why are you using IDs in 1.8 anyway?
Chisel Facades: For all your decorative pipe-hiding needs.
Please don't PM me to ask for help or to join your mod development team. Asking your question in a public thread preserves it for people who are having the same problem in the future. I'm not interested in developing mods with people.
What kind of ID do you mean? If you want a lapis asuli dye item then you just need to put Items.dye into an ItemStack and set the property appropriately.
That web site already gives the ID number for lapis: Lapis Lazuli - ID: 351:4
And I think Item.getIdForItem() is that ID -- in the Item class you can see that dye is registered as 351. So you already know how to do it.
Maybe the point you're missing is that an item in the game is really an ItemStack even if there is just one of them. And that has metadata to indicate what subtype (like what color dye).
Anyway, what are you trying to do? It is very rare to have to use item IDs in modding.