If you are referring to the I-phone/adroid Logo game, you are most likely referring to the Opel logo.
The Black Circle was created on 2009-08-11.
Usually a circle with a star in it. Although on some maps it may be a circle with a dot in it.
A neutron star or a pulsar, or a black hole.
For many maps, major cities (e.g. population over 1,500,001) use a large solid black circle as the symbol. Cities with populations 1,000,001 to 1,500,000 and cities up to 1,000,000 each use a smaller solid black circle. State capital often uses a solid black star symbol on a map.
It is Converse
Converse has a white circle with a blue star in it