We encourage any Gemologist or Appraiser looking for expert training to take an Ivory ID Workshop.
Great effort is taken to give both detailed and in depth training in determining true characteristics of Elephant Ivory, other Ivory types and Faux Ivory imitations.
65-70% hydroxyapatite Ca5(Po4)3OH, plus collagen and elastin protiens
Crystal system: none, amorphous
Color; White, Yellow, yellowish white (turns yellow with age)
Refractive Index: 1.54
Mohs Hardness: 2.5 - 2.75
Specific Gravity: 1.70 - 2.0
UV Reaction: fluoresces weakly to strongly bluish white to LW, less to SW
Below are some unwanted treatments you might want to explore.
MAKING IVORY LOOK OLDER:
Quite often one finds, in the ivory carving market, that criminals are carving new ivory and selling it as old or antique or even using other materials such as bones or man-made ivory and selling that off as real ivory. In order to get higher profits for their work, these people try to discolor the carved objects to make them look old. There are various ways of doing this, none of which can escape careful scrutiny. But the unwary can be deceived.
1. One method is to heat up the ivory in strong tea or soak it in coffee for extended periods, even weeks of months.
2. Another is to soak the ivory in turpentine and then expose it to strong sunlight for three or four days.
3. A method used to replicate the slight cracking that occurs sometimes with old ivory is to place it alternately in a furnace and a freezer so that the alternate heating and freezing causes the surface to crack.
4. Another approach is to expose the ivory to smoke which causes it to discolor and resemble antique ivory. Sometimes tar is used which deposits an even layer of color on the new ivory. This is fairly easy to detect because a cloth with organic solvent or soap and warm water will remove the color and bring out the luster of the new ivory.
One way to detect any of these methods of “aging” the ivory is to examine the exterior surface and compare it to the inner carvings. If the ivory has aged naturally. The outer layer discolors differently from the inner parts where the ivory has been carved. In other words it does not discolor uniformly. However, the false aging affects all parts of the piece the same so the “aging” appears uniform throughout. This is a sign of false aging.
One needs to be aware of signatures and styles. The famous, ancient ivory carvers–the really good ones–were allowed to sign their pieces. Some of the later forgers would also try to duplicate the signature of the old master to forge the piece so that it could achieve a much higher price. So one needs to be vigilant for fakes and have them checked and verified by experts if there is any question. It would be very hard to really replicate the style and the forge the signature of a real master.