The present invention provides a reflective type liquid crystal display device and fabricating method thereof, by which resolution is enhanced in a manner of representing two colors from one sub-pixel. A process for producing a nitride crystal, which comprises bringing a reactant gas reactive with ammonia to form a mineralizer, and ammonia into contact with each other to prepare a mineralizer in a reactor or in a closed circuit connected to a reactor; and growing a nitride crystal by an ammonothermal method in the presence of the ammonia and the mineralizer. The reversible alkali beam cell also includes a second chamber configured as the detection chamber during the first time period and as the reservoir chamber during the second time period.