Distinguishing true-False /Replica materials

Tortoiseshell: this is the most frequently imitated. Long before the prohibition of turtle hunting, this magnificent material was reproduced.

First with dyed horn, then with gelatin, celluloid and other plastics. 

Imitations may be either roughly or amazingly well done. And sometimes, only a trained eye recognizes the difference. 

Some tips:

Proceed by elimination

 - With a razor blade, scratch a hidden part without causing damage (the inner side of a tooth, for example) and get a few tiny chips of material in a dish. Light it with a match (move the object itself away). If there is a small explosion (pop!) and if  it smells camphor or something chemical, you have celluloid or plastic. If a smell of roasted pig emerges, it is therefore keratin horn or shell. 

- If the object has bite marks from weevils, this can only be a natural material ie horn or tortoiseshell 

- To distinguish one from the other, have a look at its transparency. Horn is fibrous, while shell is dense, with a few internal chaps. The mottled aspect must be random.

Ivory: genuine ivory is heavy, dense, veined. Imitations are various;  what is called in French "ivoirine" is powder of ivory agglomerated with a binder, but there are no veins. "French Ivory» is only plastic with very unnatural parallel veins. Be careful also with bone items sold as ivory. The grain of  bone is not smooth, making polishing difficult. Observe therefore its brilliance: polished bone remains dull, whilst ivory is bright.

Kingfisher feathers: you will only find these on Chinese jewelry. 

They are expensive and scarce. Many sellers renovate or make  nineteenth century style ornaments with artificially colored feathers from common birds. The result is poor because the special iridescence of these feathers is inimitable

Last century, this tiny bird came near to extinction , but today it is still hunted for its feathers, mainly for restoration or new decorations. However, techniques have changed since application onto metallic surfaces requires a thoroughness which isn't worthwhile in this modern day and age. Barbs are roughly applied, and do not follow the precise outlines.

These tips will make you more aware but it takes time to become expert in these matters! Experience is essential.

Genuine tortoiseshell. USA, late 19th c.
Celluloid imitating tortoiseshell. USA, late 19th c.
Blonde tortoiseshell. SAPIO workshop. France, late 19th c.
Celluloid imitating blonde tortoiseshell. USA, 1920
Genuine clear horn. France, 1900-10
Celluloïd imitating clear horn. USA, 1900-10
Genuine kingfisher feathers. China, 19th c.
Faux kingfisher feathers. China, 20th c.
Genuine ivory. China, late 19th c.
"French ivory" celluloid. France, 1930
Genuine dyed ivory. Africa, 20th c.
Dyed bone. Africa, 20th c.