Saric, I now remembered something; you can't craft mechanical devices with deep crystal. Also can't craft deep crystal bows. But I would allow ammunition crafted from deep crystal. The price for deep crystal allows 50 of such ammunition to be made. But if you have quiver of ehlonna you get ammunition back if it's not broken somehow (I know quiver normally gives magical storage room than returning but years I have ruled in my tabletop group it grants returning for ammunition).