Tortoise Shell

Tortoise Shell

Ornamental tortoise shell is obtained from the carapace or shield of the hawksbill turtle found in the Malay Archipelago, West Indies and Brazil. The colour is mottled and mainly
a translucent yellow with brown mottling.

Generally thicker shells are used to make jewellery which is brown in color with white spots.


Properties
Chemical Composition: 
Complex Protein (keratin)
Classification / Type: 
Obtained from the carapace of a sea turtle.
Colors / Varieties: 
Mottled yellow and brown. Transparency: Translucent to Opaque.
Crystal System / Forms: 
None. Amorphous.
Hardness: 
2.5
Specific Gravity: 
1.29
Cleavage / Fracture: 
None / Uneven.
Optic Character: 
A.G.G.
Lustre: 
Oily to waxy.
Refractive Index / Birefringence: 
1.55 / Nil.
Pleochroism: 
None.
Dispersion: 
None.
Magnification: 
Mottled sections show spherical spots of color. Larger numbers of dots give rise to deeper shades of color.
U.V. Fluorescence: 
Yellow portions give blue white fluorescence.
Spectrum: 
None.
Treatment (Enhancement): 
Colored impregnation (dyeing)
Specific Tests & Remarks: 
  • Sectile and brittle.
  • Thermoplastic nature which softens in boiling water; used to produce large sheets.
  • Excessive heat darkens the color.
  • Burnt hair odor.
Synthesis: 
None.
Simulants (with key separation tests): 
  • Most commonly plastic (bakelite).
  • Dust and scrapings of tortoise shell are softened and moulded, also dyed to produce darker colors.
  • Doublet - tortoise shell on a plastic base.
Geological Occurrence: 
-
Sources: 
Shell of turtles which are found at Indonesia, Indian Ocean, Malay Archipelago, Brazil and West Indies.
Cuts & Uses: 
Cabochons, used for inlay work, carvings, decorative combs and other items.

Did you know?

Jewellery is one of the most bought products online. An estimated $1 billion USD of diamonds are bought annually via the Internet. Over 40 million people use the Internet to trade!

In Germany, the garland of ambers is hung around the necks of the infants, so that their teeth might come out without much trouble.

In Turkey, people fix a piece of amber in the hubble-bubble, dogged by an age old belief that the presence of the jewel would destroy all the germs and no disease would spread, even after many have dragged their puffs from it.

In Greece, people think if wine is poured into the cups made of amethyst, one does not get drunk after drinking that.

In Rome, a talisman having coral pieces is considered very auspicious to quell the bad spells of evil look. The Romans were in the habit of hanging chains made of ancient coral pieces from the cradle of the infants to protect them from evil effects.

In China, people wear rings studded with tiny conch or oyster shells as they believe it cures all aches such as stomach ache, worms and like.

In India, pendants made of silver and studded with pearls are hung from the necks of the children to save them from any bad effects.

Greeks still believe, if women wear blue sapphires then no sense of immorality would pollute their mind nor can any fear of the supernatural can trouble them.

The Pope Innocent III had circulated an order asking all the priests wear blue sapphire, so that morality can be strengthened.

It is said about turquoise, that when the stone changes its color into yellow, it actually signals bad times to the person who wears it.

It is believed that a turquoise gifted to a friend or a lover turns his or her life into one of happiness and good luck.

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