How is my glitter order measured?

How is my glitter order measured? 
    PLEASE NOTE- It's Pretty Personal measures glitter by VOLUME, not weight. 
    Please note: Glitter may settle in shipment.
    If glitter seems like it may be a little less in the bottle upon arrival, please pour contents of the entire bottle out and refill the bottle to see the volume fill back up. 
    Weight: Weight is determined by the heaviness, or mass, of the particular item, and is measured with the use of a scale.
    Volume: Volume is the amount of space that an item you are measuring takes up.
    It's Pretty Personal has decided to measure out glitter products by VOLUME to assure that everyone is getting the same amount of product, across the board, regardless of the product weight. 
    We sell our glitter in shakers at NO EXTRA charge to you! 
    So we try our best to make sure that when receiving your products they all equal the same to the eye. 
    Each company has the right to run however they decide works best for them and this is what works for us and our customers.