Diamond spray comes in different carat designations: 10, 15, etc..

I understand the meaning of grit size (.25, .5, etc.) but am not sure of the significance of different carat designations. Can anyone enlighten me?

My *guess* is that it is a measure of how much diamond is in the mix. Is that measured in carats per some volume of liquid? For example, 15 carat would have half again as much actual diamond grit in the same quantity of 10 carat spray mix.

If I am right about that it would be OK to refresh a strop with 15 carat .5 micron spray if the strop was initially sprayed with 10 carat .5 micron spray.