1. I was showing my friend from Brazil the milky-way that you can see clearly in Northwest Montana it was about 11:30pm Mountain time. 2.We were walking back to my house and looking at the sky when a Bright and large "orb" came floating slowly above and out from behind a nearby mountain. 3.When we saw it we both were surprised and the Brazilian, he was scared more than I. We were both fascinated, it was immediately recognizable as a nontraditional flying craft. It was Obviously too large, too slow, and too silent to be a plane or helicopter and both are uncommon in my area. 4. The Craft/object was moving slowly, silently, and steadily Northeast. it "floated" directly above us at around 5000ft the closest large mountain nearby is about 7000ft and this craft was not as high up as the top. As it passed over us and the surrounding pasture it was emitting a bright white light similar to a welding torch. What I think is somewhat interesting is I waved my hands shouted at it and flicked a lighter and I cant be sure but it almost seemed like it "realized" we were there and its lights began to dim to nothing and it revealed what I recognize/(believe to be) as an Isosohedron made of what looked like Hot metal. it seemed to cool off after diming its lights off and as it did this the hot metal look faded and it became no longer visible against the night sky as it moved off in the distance. from what i saw it was clearly a large solid, metallic geometric shape because of the size it appeared to be at its altitude. It was appearing about the size of my little fingers nail while at about 5000ft so I guess it was actually somewhere around 20-40 feet around in circumference. 5. I was surprised and mildly fearful/cautious but I was more interested and in hindsight maybe too curious, this curiosity overcame any fear I was feeling. My Brazilian friend was scared and told me to stop trying to get its attention. He said he had no doubts that what he saw was unique and a UFO. I think it is a craft of some metal that is clearly developed by an intelligence that understands geometry. I also think it that it was not "intending" to be seen.6. I think it obviously noted our presence and then began to behave differently by "turning off" its light and cooling and fading into the dark sky around it becoming no longer visible.