Islamic Interpretation of Dreams (Ibn-i Sirin):

Counting specks of dust or gathering them in a dream means trials, injustice, aggression, or temptations.

Specks of dust in a dream also represent one’s progeny, money, longevity, or they could represent soldiers, weak people, or God’s soldiers.

Seeing a room full of dust in an unusual place, or a closed place where they usually do not gather means knowledge, or they could mean immeasurable wealth.