Small copper coloured craft, flat based

In 2010, I was standing alone on my terrace in Brazil looking at the large garden when I realised I was being 'watched'.
Literally, just out of arm's reach, which I immediately acknowledged, and at head height, was a wingless, motionless perfectly still object which appeared to be monitoring me.
The object was small and appeared to be hard, opaque, shiny, and copper in colour.
It's size, being no bigger than two inches, it's shape was semi-circular with a flat base.
There were no visible 'eyes' or markings, it made no sound, and just stayed motionless in mid air.
In order to see if it was observing me I took one sideways step, which effectively put me the other side of a wooden pillar, and stood motionless.
The object again appeared directly in front of me, eye to 'eye'.
After a few seconds it vanished whilst I was observing it, no sound and moved faster than the human eye could detect.