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. | + | ( 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]]. | ||
Revision as of 12:36, 16 December 2022
Description
( 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.)
Risks
- No significant hazards.
- ThermoFisher: 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
| Mohs Hardness | 3.5 - 4.0 |
|---|---|
| Density | 2.93-2.95 g/ml |
| Refractive Index | 1.530 - 1.686 |
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