Editing Onycha (section)

===Operculum===
{{main|Operculum (gastropod)|Unguis odoratus}}
Some writers believe that onycha was ''[[Unguis odoratus]]'', the fingernail-like [[Operculum (gastropod)|operculum]], or trap door, of certain [[sea snail]]s, such as ''[[Strombus lentiginosus]]'', ''[[Murex anguliferus]]'', and ''[[Onyx marinus]]''. It may be the operculum of a snail-like mollusk found in the Red Sea.<ref>Onycha, Encyclopaedia Judaica, 2008</ref> This operculum is the trap door of a shell, called by the [[Latins (Italic tribe)|Latins]] ''Conchylium''. These opercula may be of different sizes, but their overall shape is that of a claw, which is the origin of the name ''Unguis odoratus''. The name ''Blatta Byzantina'' is occasioned by its having usually been imported from [[Constantinople]], the ancient [[Byzantium]]. In antiquity the operculum was used as an ingredient in incense. The Babylonian Talmud recorded that onycha was rubbed with an [[alkali]] solution prepared from the bitter [[vetch]] to remove impurities,<ref name="Rambam on Maaser Sheni 2:4">Rambam on Maaser Sheni 2:4</ref> it was then soaked in the fermented berry juice of the [[Caper]] shrub,<ref name="Talmub Babli">Babli, Keritut:6a</ref> or a strong [[white wine]], in order to enhance its fragrance. 

Although it was forgotten in the West after the fall of the [[Roman Empire]], Murex opercula are still commonly used as an ingredient in traditional North African and Middle Eastern bakhoor (granulated [[incense]]), traditional Indian ''choya nakh'' [[attar]] (produced by [[dry distillation]] of Murex opercula <ref>{{cite journal |last1=Nongmaithem |first1=Bijayalakshmi Devi |last2=Mouatt |first2=Peter |last3=Smith |first3=Joshua |last4=Rudd |first4=David |last5=Russell |first5=Michael |last6=Sullivan |first6=Caroline |last7=Benkendorff |first7=Kirsten |title=Volatile and bioactive compounds in opercula from Muricidae molluscs supports their use in ceremonial incense and traditional medicines |journal=Scientific Reports |date=12 December 2017 |volume=7 |issue=1 |page=17404 |doi=10.1038/s41598-017-17551-3|pmid=29234065 |pmc=5727037 |bibcode=2017NatSR...717404N }}</ref>), and quite substantively in East Asian incense.<ref>{{cite web |url=https://www.kyarazen.com/de-mystifying-onycha/ |title=De-mystifying Onycha |date=23 February 2016}}</ref> From this perspective, some argue that this is the most likely source of onycha.