Gypsum —-is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO₄·2H₂O. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk. Gypsum also crystallizes as translucent crystals of selenite. It forms as an evaporite mineral and as a hydration product of anhydrite.
Chalk —is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor.
Diatomaceous Earth —- is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. The typical chemical composition of oven-dried diatomaceous earth is 80–90% silica, with 2–4% alumina (attributed mostly to clay minerals), and 0.5–2% iron oxide.[1]
They make Sheetrock over in Antioch here in the PRCA, but they ship the Gypsum up from Mexico now 🙄
If using DE, be sure to get the food grade label. Not the DE used in filters (such as swimming pool).
Actually, Diatomaceous Earth is made from the fossilized remains of tiny, aquatic organisms called diatoms. Hence the name.