  Advancement of diamond based photonic circuitry requires robust fabrication
protocols of key components, including diamond resonators and cavities. Here,
we present 1D (nanobeam) photonic crystal cavities generated from single
crystal diamond membranes utilising a metallic tungsten layer as a restraining,
conductive and removable hard mask. The use of tungsten instead of a more
conventional silicon oxide layer enables good repeatability and reliability of
the fabrication procedures. The process yields high quality diamond cavities
with quality factors (Q factors) approaching 10$^$4. Finally, we show that the
cavities can be picked up and transferred onto a trenched substrate to realise
fully suspended diamond cavities. Our fabrication process demonstrates the
capability of diamond membranes as modular components for broader diamond based
quantum photonic circuitry.
