I got this plot by narrowing down the diamond dataset in ggplot2. I did this by sorting for a x limit, cut, etc.
library(ggplot2)
qplot(price,carat,data=diamonds,cut="Ideal",color=clarity) + xlim(2500,3000) + ylim(1,1.6)

How do I extract this data? Does this represent its own subset of the large dataset? So that I can do things like get the mean price, max carat values, etc. ?
You can get just the points that appear in that plot: