How many teaspoons does 4 grams of ginger powder equal?

I wanted to know this for magnesium oxide powder so I did a google search and found two urls which indicated that 1 tsp of baking powder is 5 grams. So, doing the math, and assuming baking powder and ginger powder have roughly the same density, 4 grams would be .8 of a teaspoon! www.joyofbaking.com/bakingsoda.html