A large (10 – 12’ diameter) very bright, rotating ball of light was observed at about 10 p.m. on August 2, 1997 by Robbert (age 16) and sister Madelon (age 10). It was immediately outside the balcony windows off a bedroom of their home in Hoeven, The Netherlands. They observed the light from this bedroom. A white powder was found lying on the floor outside the balcony doors and adhering to the glass door after the ball of light was seen. Following are photographs of the material as found.
The white material is identified as basic magnesium carbonate with the following approximate chemical structure: (MgCO3)4•Mg(OH)2•5H2O. A very small amount of calcium carbonate may also be present. It is unknown why this material appeared after the UFO event. Known uses for basic magnesium carbonate follow: magnesium salts; fireproofing; heat insulation and refractory; rubber reinforcing agent; inks; glass; pharmaceuticals, dentifrices and cosmetics; free-running table salts; antacid; making magnesium citrate; filtering medium. It’s used in foods as a drying agent, color retention agent, anticaking agent carrier.