Pseudo-pleochroic Calcite in Recrystallized Shell-Limestones
By: Hudson, J.D
.
Material type: ![Article](/opac-tmpl/lib/famfamfam/AR.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
![](/opac-tmpl/bootstrap/images/filefind.png)
Item type | Current location | Collection | Call number | Status | Date due | Barcode |
---|---|---|---|---|---|---|
![]() |
Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002547_77 | ||
![]() |
Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002547 |
Limestones consisting of recrystallized shells of lamellibranchs, originally composed of aragonite, contain a brown-coloured calcite which is strongly pleochroic. Maximum “absorption’ corresponds to the extraordinary ray. The effect is shown to be a pseudo-pleochroism, caused by scattering of the extraordinary ray by inclusions, which follow the shell structure, in the calcite. Aragonite shells, which have not recrystallized, show a pseudo-pleochroism of similar colour but reversed sign. The inclusions originate in the conchiolin of the lamellibranch shell; their present nature is not known. Their progressive destruction by thermal metamorphism is described.
There are no comments for this item.