Hi Murbade,
firstly check to see if your cream is in date because my first thought was that they might be mould spores.
However, if the cream is in date, then I would check to see if you are mixing it in a metal bowl with a metal whisk. If so the clash of metal on metal can chip off shards or flecks of the bowl and can cause this to enter your cream which may then appear as black or grey specks in your mixture.
Either way, I wouldn't consume it and would start fresh, maybe this time with either a silicone whisk or a plastic bowl.