One of the ways to know if this is real turquoise or dyed howlite is by what the original cost was. If it was on the higher end usually it is real turquoise. Hope this helps.
I have been told by experts that 85% of the turquoise out there is fake. I can't tell with certainty if your necklace is real or not, though if it has any howlite I don't think it would be more than the four blue stones. The pendant is anybody's guess...jasper maybe?