Editing Perlite (section)

==Properties==
[[File:Perlite-nps-02316.jpg|thumb|Perlite boulders with [[fireweed]] in foreground]]
Perlite softens when it reaches temperatures of {{convert|850|–|900|°C}}. Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume. The expanded material is a brilliant white, due to the reflectivity of the trapped bubbles. Unexpanded ("raw") perlite has a [[bulk density]] around 1100&nbsp;kg/m<sup>3</sup> (1.1 g/cm<sup>3</sup>), while typical expanded perlite has a bulk density of about 30–150&nbsp;kg/m<sup>3</sup> (0.03–0.150 g/cm<sup>3</sup>).<ref>{{Cite journal|title = Perlite toxicology and epidemiology – a review|journal = Inhalation Toxicology|date = 2014-04-01|issn = 0895-8378|pmc = 4002636|pmid = 24601903|pages = 259–270|volume = 26|issue = 5|doi = 10.3109/08958378.2014.881940|first1 = L. Daniel|last1 = Maxim|first2 = Ron|last2 = Niebo|first3 = Ernest E.|last3 = McConnell| bibcode=2014InhTx..26..259M }}</ref>