What is Oolitic Aragonite?

oolitic aragonite, ooids, crystalline morphology

A Closer Look at Oolitic Aragonite

Oolitic Aragonite is a polymorph of Calcium Carbonate (CaCO₃). While it has the same chemical composition of calcite/limestone, it is morphologically different, which affords it a number of benefits in various industries.

Oolitic aragonite in its natural form looks a lot like sand, but upon closer inspection, you will see that the grains are “oolitic," which means egg-shaped. The round, spherical grains of oolitic aragonite also have a different crystalline morphology from calcite or limestone. Oolitic aragonite is extremely pure, has a high surface area, high negative zeta potential, and is biogenically renewable. It is safe and easy to handle.

Calcean offers oolitic aragonite in its natural granular form (SandyCal) or milled into a fine powder (OceanCal). Used in agriculture, paints/coatings, bioplastics, play sand, glass, and more, oolitic aragonite is a versatile mineral perfect for meeting your sustainability goals without sacrificing performance.

How Does Aragonite Form?

The formation of aragonite (biogenic CaCO₃) occurs as a phenomenon described as a “Whitings” event. The “Whitings” are an accumulation of precipitated calcium carbonate induced by photosynthesis, occurring in blooms of phytoplankton, which seasonally enter the warm shallow waters of the Bahamas. Whitings have been observed on satellite imagery and aerially since the ‘60s. They appear as milky white clouds in the water.

Within the approximately 400 sq. mi. leased harvesting area, roughly 2 million tons of aragonite is generated each year. The precipitated aragonite forms concentric layers around a nucleus, making oolitic aragonite. ASTM D6866 testing confirms the renewability of oolitic aragonite and its biobased origins. Unlike ground calcium carbonate (limestone, etc.) which is from nonrenewable fossil sources, oolitic aragonite is the only calcium carbonate from a renewable and sustainable source.

whitings on the banks of The Bahamas, calcium carbonate precipitation events

Oolitic Aragonite vs. Ground Calcium Carbonate

oolitic aragonite deposit, underwater, sand, calcium carbonate deposit

Oolitic Aragonite

  • Renewable: ASTM D6866 Testing confirm oolitic aragonite is a renewable resource.

  • Negative Carbon Footprint (per proprietary ISO 14067:2018 study)

  • No permanent structures are erected for harvesting

  • Harvested, not mined

  • Biogenic

Ground Calcium Carbonate

  • Non-renewable, from fossil sources

  • Large carbon footprint of mining, transportation and processing

  • Carved out of the land, changes geological conditions

  • Habitat loss/destruction

  • Permanent changes to the local environment