Yes that sand used in marine aquaria is mined from underwater areas in the Bahamas and a few other tropical places and even some inland places (ancient inland seas) with large calcium carbonate deposits/geology. It is from the local corals eaten and pooped out by fish and the shells shellfish and foraminifera, a tiny shellfish which is amazing that they occur in such numbers to make up a large component of the sand in those areas. In fact there has been a debate about whether the practice of mining it is sustainable.
In most of the world, beach sand is mostly quartz or other silica based minerals derived from weathering of rocks.
The black sand beaches in Hawaii and other areas with high volcanic activity is pretty cool too. Then there are a four places with green sand that has a mineral called olivine makes it green. Ive never seen that but it looks really cool in the pictures and kind of weird if youre used to the iconic white sand beaches.
The things that effect sand color on beaches is pretty fascinating.
Oolitic Aragonite: Nature’s Renewable Sand from the Ocean Beneath the gin clear waters of The Bahamian banks lies a unique mineral that looks much like sand but is unlike the san
www.calcean.com
Where does beach sand come from? The sand found on a specific beach is created by its surroundings. It’s unique to that beach—like a fingerprint.
www.whoi.edu
Sands covering our beaches across the world can teach us a lot about Earth’s history.
www.sciencefriday.com
Most beach sand color ranges from pale cream to golden to caramel, but in select places around the world, sand can be red, pink, orange, chocolate, gold, purple, green, or black.
coastalcare.org