Black triangle observed at dusk, stationary seemed hanging in the air not subject to gravity, no noise noticeable from my place, estimated at 500, 600 ft from me, 100 ft altitude. triangle size estimated 50/70 ft. very dark black. observation for a few seconds, i can't tell when it appeared, but it disapperead in a glance, without a noise. i am just now reporting it more than 6 years after observation as i could not understand what i saw, and did not relate this to an ufo sighting, until i recently saw a tv show on ufos where black triangles were mentioned.