Chinese drywall
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"Chinese drywall" refers to an environmental health issue involving defective drywall manufactured in China, imported to the United States and used in residential construction between 2001 and 2009 –
The copper coils on this air conditioner unit are blackened and corroded.
The green and red coloration in these copper components is an indicator that they were subject to typical corrosion, and not as a result of hydrogen sulfide emitted from contaminated imported drywall.
Gypsum
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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 o
Gypsum from southwest France (27 × 22 cm)
Gypsum crystals are soft enough to bend under pressure of the hand. Sample on display at Musée cantonal de géologie de Lausanne.
Large gypsum crystals in Lechuguilla Cave's "chandelier ballroom"
Gypsum crystals in the Cave of the Crystals in Mexico (person at lower right for scale)