In Hawaii, it's illegal to take more than a play pail of sand from any beach since the state spends millions restoring its beaches annually.
Chapter 171.58.5 of Hawai`i Revised Statutes states:
Prohibitions. The mining or taking of sand, dead coral or coral rubble, rocks, soil or other marine deposits seaward from the shoreline is prohibited with the following exceptions:
(1) The taking from seaward of the shoreline of such materials, not in excess of one gallon per person per day for reasonable, personal, noncommercial use;
The other three exceptions are to allow replenishment or protection of public shoreline areas, clearing of stream mouths, and cleaning of areas seaward of the shoreline for state or county maintenance.
Taking of sand on a regular basis for use as a product for sale would be considered as constituting a commercial use, which is not permissible.
BTW, taking any sand or rubble from any black sand beach is illegal. However, authorities usually look the other way if you take only an ounce or 2.