Hovering object just above rooftops

Large object that appeared to be hovering approx 50-100 ft above the rooftops of the nearby homes. The undercarriage appeared as is if I was looking at a very large cruise ship size boat. It appeared as if an iridescent light was moving through different parts of the object and wherever it moved to you could see through the object to the night sky behind it. I did not observe any type of windows or exhaust. There were 2 large what appeared to be pillars sticking up on top on each end but otherwise the top was difficult to see due to the iridescent light sweeping through it and around it. Color was varying from dark brown to black color in different areas. There was no sound coming from this object. No exhaust. I recall the wind, trees and all active life I usually hear at night making sounds stopped as if time closely around the object had stopped as it hovered. It was an extended sighting so I went in my home to wrap my brain around it and went back outside and it was still there. Unfortunately cell phone use was uncommon in the early 90s and we didn't have a camera so no photos.Total estimate time it hovered was 30-45min then it quietly floated away but once it got about 500 or so feet away it appeared to suddenly become invisible. After the sighting I do not recall the remainder of the night and I unfortunately suffered at least three periods within the same week of missing time periods in 5 hour blocks.