Talk:Fate/Grand Order Fes. 2018 ～3rd Anniversary～/@comment-36402971-20180731114034/@comment-34364075-20180731115217

They keep separate records on which quartz are paid and which ones are free.

So if you bought 4 quartz yesterday + 1 free bonus, and today you buy 8 quartz and 2 bonus, you'd have a total of 12 paid quartz and 3 free quartz.

Only the paid quartz can be used in the lucky bag, and the amount of free quartz you have won't matter. You don't have to spend the free quartz either.