Editing Alum (section)

===Alum found at archaeological sites===
The western desert of Egypt was a major source of alum substitutes in antiquity. These [[evaporite]]s were mainly {{chem|Fe|Al|2|(SO|4|)|4|·22 H|2|O}}, {{chem|Mg|Al|2|(SO|4|)|4|·22 H|2|O}}, {{chem|NaAl(SO|4|)|2|·6 H|2|O}}, {{chem|Mg|SO|4|·7H|2|O}} and {{chem|Al|2|(SO|4|)|3|·17 H|2|O}}.{{refn|name=Picon-etal-2005-lAlun|
{{cite conference
 |author1=Picon, M.
 |author-link=Maurice Picon
 |display-authors=etal
 |date=2005
 |title=L'alun des oasis occidentales d'Egypte: Researches sur terrain et recherches en laboratoire}} 
}} <ref name="Borgard-Brun-Picon-2005-06-07-alunMedit" />
The [[Ancient Greece|Ancient Greek]] [[Herodotus]] mentions Egyptian alum as a valuable commodity in ''The Histories''.<ref name=Herodotus-c430ʙᴄᴇ-Hists/>

The production of potassium alum from [[alunite]] is archaeologically attested on the island [[Lesbos]].{{refn|name=Archontidou-2005-alunMedit|
{{cite conference
 |last=Archontidou |first=A.
 |date=2005
 |title=Un atelier de preparation de l'alun a partir de l'alunite dans l'isle de Lesbos
 |language=fr,grc
}}
<ref name="Borgard-Brun-Picon-2005-06-07-alunMedit" />
}}
The site was abandoned during the 7th&nbsp;century&nbsp;CE, but dates back at least to the 2nd&nbsp;century&nbsp;CE. Native ''alumen'' from the island of [[Melos]] appears to have been a mixture mainly of alunogen ({{chem|Al|2|(SO|4|)|3|·17 H|2|O}}) with potassium alum and other minor sulfates.{{refn|name=Hall-Jones-2005-alunMedit|
{{cite conference
 |first1=A. J. |last1=Hall 
 |first2=E. |last2=Photos-Jones
 |date=2005
 |title=The nature of Melian alumen and its potential for exploitation in Antiquity
}}
<ref name="Borgard-Brun-Picon-2005-06-07-alunMedit" />
}}