Path: utzoo!attcan!uunet!wuarchive!emory!gatech!mcnc!beguine!hasty!jfm
From: jfm@hasty.med.unc.edu (John F. Miller)
Newsgroups: sci.bio
Subject: Re: ivory vs. bone
Message-ID: <1453@beguine.UUCP>
Date: 29 Oct 90 01:53:57 GMT
References: <6102@videovax.tv.tek.com>
Sender: usenet@beguine.UUCP
Reply-To: jfm@uncmed.med.unc.edu (John F. Miller)
Organization: UNC School of Medicine, Dept. of Pharmacology
Lines: 44

In article <6102@videovax.tv.tek.com> chrish@videovax.tv.tek.com.UUCP (Chris Hawes) writes:
>
>       I'm seeking info on how to distinguish the difference between
>carved and polished bone vs. carved and polished ivory. . .  

Bone and ivory have very similar characteristics in terms of refractive
index, hardness, specific gravity, and general appearance.  The primary
means of differentiation involves microscopic observation.  At 20X-50X,
bone shows minute cavities (lacunae) or dark bands, depending on the 
orientation.  Elephant ivory displays a unique "engine-turned" appearance
on cross section due to the spiral structure of the tusk.  Elephant ivory
may also display straight or curved grain lines or wavy canals.  Ivory
from several other sources (hippopotamus tooth, wart hog tusks, narwhal
tusks, sperm whale) more closely resembles elephant ivory than bone, but
the differences in appearance are generally rather subtle.  There are also
two vegetable products that resemble ivory -- corozo nut and doum-palm nut;
they can usually be differentiated by refractive index or specific gravity.
Consult your local gemologist for more details (shop around, though, since
the average jeweler will not likely be able to tell the difference).


>. . . Obviously, the cost of ivory today
>is very high, but what is the cost of bone?  And what type of bone would
>have been used at that time to make handcrafted items?  Should I trust
>an antique dealer with this question?   How difficult is it to tell the
>difference?

Actually, the cost of ivory has plummeted over the last couple of years,
since international trade of elephant ivory has been banned by most nations,
and public demand has dropped due to elephant conservation efforts.  The
cost of bone (usually cow bone) is minimal.  Most of the value of finished 
items now is a function of labor and artistic merit.

I would advise you to consult with not one, but several antique dealers
who frequently do business with this sort of item.  In the world of antiques,
as elsewhere, "90% of everything is crap".  Take several opinions and ignore
those that do not have the ring of truth.

-- John Miller, 
Gemcutter/Graduate Gemologist (oh, yeah, and Analyst Programmer)

  John F. Miller
  Department of Pharmacology, UNC-CH School of Medicine
  1026A FLOB  (231H) CB#7365, Chapel Hill, NC  27599    Tel: (919) 966-6966