A quart of blackberries typically weighs between 20 to 24 ounces (567 to 680 grams).

A quart of blackberries generally weighs around 20 to 24 ounces (567 to 680 grams), depending on the size and density of the berries. This measurement is based on the volume of a quart container, which holds approximately 4 cups of berries. The weight can vary slightly due to factors like berry size, moisture content