Difference between revisions of "Shell"

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== Description ==
 
== Description ==
 
[[File:1994.420-SC1902.jpg|thumb|Mask with shells<br>MFA# 1994.420]]
 
[[File:1994.420-SC1902.jpg|thumb|Mask with shells<br>MFA# 1994.420]]
The hard outer covering or case of an animal, mollusk, insect, nut, or egg.  
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( Biology) The hard outer covering or case of an animal, mollusk, insect, nut, or egg.  
  
 
For more information see [[eggshell|eggshell]], [[seashell|seashell]], [[oyster%20shell|oyster shell]], [[tortoiseshell|tortoiseshell]], and [[walnut%20shell|walnut shell]].
 
For more information see [[eggshell|eggshell]], [[seashell|seashell]], [[oyster%20shell|oyster shell]], [[tortoiseshell|tortoiseshell]], and [[walnut%20shell|walnut shell]].
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shells; seashell; tortoiseshell; eggshell; coquille (Fr.)
 
shells; seashell; tortoiseshell; eggshell; coquille (Fr.)
[[[SliderGallery rightalign|Aragonite 2.TIF~FTIR (MFA)|Aragonite (HU Min. Museum 116189), 50X, 785 nm copy.tif~Raman (MFA)|aragonite.jpg~Chemical structure]]]
 
 
== Risks ==
 
* No significant hazards. 
 
* ThermoFisher: [https://www.fishersci.com/store/msds?partNumber=AC423510025&productDescription=CALCIUM+CARBONATE+99%2BACS+2.5KG&vendorId=VN00032119&countryCode=US&language=en SDS]
 
== Physical and Chemical Properties ==
 
* Reacts with acids to evolve carbon dioxide. 
 
* Aragonite is harder and denser than calcite 
 
* Fracture = uneven to splinter
 
* Luster = greasy or pearly 
 
* Streak = white   
 
* Fluorescence = variable
 
* Birefringence = strong (0.155) showing interference colors
 
* Straight extinction
 
 
{| class="wikitable"
 
|-
 
! scope="row"| Mohs Hardness
 
| 3.5 - 4.0
 
|-
 
! scope="row"| Density
 
| 2.93-2.95 g/ml
 
|-
 
! scope="row"| Refractive Index
 
| 1.530 - 1.686
 
|}
 
  
 
==Resources and Citations==
 
==Resources and Citations==

Latest revision as of 12:37, 16 December 2022

Conch shell trumpet
MFA# 1988.1214

Description

Mask with shells
MFA# 1994.420

( Biology) The hard outer covering or case of an animal, mollusk, insect, nut, or egg.

For more information see Eggshell, Seashell, Oyster shell, Tortoiseshell, and Walnut shell.

Synonyms and Related Terms

shells; seashell; tortoiseshell; eggshell; coquille (Fr.)

Resources and Citations

  • Gem Identification Lab Manual, Gemological Institute of America, 2016.
  • Oppi Untracht, Jewelry Concepts and Technology, Doubleday & Co., Inc., New York City, 1985
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962
  • Art and Architecture Thesaurus Online, http ://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000