Gypsum
<p >Gypsum is used in a wide variety of applications:</p>
<ul >
<li >Gypsum board<sup id="cite_ref-17" class="reference" ><a href="http://en.wikipedia.org/wiki/Gypsum#cite_note-17" >[18]</a></sup> is primarily used as a finish for walls and ceilings, and is known in construction as <a href="http://en.wikipedia.org/wiki/Drywall" title="Drywall" >drywall</a> or plasterboard.</li>
<li ><a href="http://en.wikipedia.org/wiki/Plaster" title="Plaster" >Plaster</a> ingredient (surgical splints, casting moulds, modeling)</li>
<li ><a href="http://en.wikipedia.org/wiki/Fertilizer" title="Fertilizer" >Fertilizer</a> and <a href="http://en.wikipedia.org/wiki/Soil_conditioner" title="Soil conditioner" >soil conditioner</a>: In the late 18th and early 19th centuries, Nova Scotia gypsum, often referred to as plaster, was a highly sought fertilizer for wheat fields in the United States. It is also used in ameliorating sodic soils.<sup id="cite_ref-18" class="reference" ><a href="http://en.wikipedia.org/wiki/Gypsum#cite_note-18" >[19]</a></sup></li>
<li >A binder in fast-dry tennis court clay</li>
<li >A wood substitute in the ancient world: For example, when wood became scarce due to deforestation on <a href="http://en.wikipedia.org/wiki/Bronze_Age" title="Bronze Age" >Bronze Age</a> <a href="http://en.wikipedia.org/wiki/Crete" title="Crete" >Crete</a>, gypsum was employed in building construction at locations where wood was previously used.<sup id="cite_ref-19" class="reference" ><a href="http://en.wikipedia.org/wiki/Gypsum#cite_note-19" >[20]</a></sup></li>
<li >A <a href="http://en.wikipedia.org/wiki/Tofu" title="Tofu" >tofu</a> (soy bean curd) coagulant, making it ultimately a major source of dietary <a href="http://en.wikipedia.org/wiki/Calcium" title="Calcium" >calcium</a>, especially in <a href="http://en.wikipedia.org/wiki/Asia" title="Asia" >Asian</a> cultures which traditionally use few <a href="http://en.wikipedia.org/wiki/Dairy_products" title="Dairy products" class="mw-redirect" >dairy products</a></li>
<li >Adding hardness to water used for <a href="http://en.wikipedia.org/wiki/Homebrewing" title="Homebrewing" >homebrewing</a><sup id="cite_ref-20" class="reference" ><a href="http://en.wikipedia.org/wiki/Gypsum#cite_note-20" >[21]</a></sup></li>
<li >A component of <a href="http://en.wikipedia.org/wiki/Portland_cement" title="Portland cement" >Portland cement</a> used to prevent flash setting of <a href="http://en.wikipedia.org/wiki/Concrete" title="Concrete" >concrete</a></li>
<li >Soil/<a href="http://en.wikipedia.org/wiki/Water_potential" title="Water potential" >water potential</a> monitoring (soil moisture tension)</li>
<li >A common ingredient in making <a href="http://en.wikipedia.org/wiki/Mead" title="Mead" >mead</a></li>
<li >In the medieval period, it was mixed, by <a href="http://en.wikipedia.org/wiki/Scribe" title="Scribe" >scribes</a> and illuminators, with <a href="http://en.wikipedia.org/wiki/Lead_carbonate" title="Lead carbonate" >lead carbonate (powdered white lead)</a> to make <a href="http://en.wikipedia.org/wiki/Gesso" title="Gesso" >gesso</a>, which was applied to illuminated letters and gilded with gold in illuminated manuscripts.</li>
<li >In foot creams, shampoos and many other hair products</li>
<li >A medicinal agent in <a href="http://en.wikipedia.org/wiki/Traditional_Chinese_medicine" title="Traditional Chinese medicine" >traditional Chinese medicine</a> called <i>shi gao</i></li>
<li >Impression plasters in dentistry</li>
</ul>
<p> </p>