A pinch is 9.5 drops according to [link|http://www.askthemeatman.com/measurement_conversion_calculato1.htm|this]. But it's not a liquid, so that doesn't help much....
One could simply use pre-measured packets like [link|http://nowfoods.com/?action=itemdetail&item_id=16490|these] (from the original link). ;-)
Cheers,
Scott.