That is a bit of a stretch, going in reverse, as the descriptions evolve from spt. However, to give you a 'general' sense:

Sand/gravel

SPT        Relative Density
0-4        very loose
5-10       loose
11-30      medium dense
31-50      dense
50<        very dense



Fine-

<2         very soft
2-4        soft
5-8        firm
9-15       stiff
16-30      very stiff
30<        hard

BridgeBuilder...pdavis1 has given you the ranges of SPT for general classification.  As he indicated, it is a significant stretch to use these in reverse.  As an example, your foundation and sitework recommendations can vary tremendously for a clean fine sand that has SPT values of less than 10 as compared to the same material with SPT values over 20.

This is a multi-parametric evaluation that should be approached from the "other" direction.