Ivory

James Tapley <jthandbook [at] aol__com> writes

>Several recently carved pieces of Siberian mammoth ivory have been
>accidentally stained with a red dye of unknown origin. The pieces
>were carved and damaged in St. Petersburg, Russia. Can anyone direct
>me to recent studies concerning the morphology and conservation of
>Siberian fossil ivory?

It's is very difficult to recognize the origin of ivory when treated
or curved. Ivory is composed of calcium-phosphate and protein. It's
very sensitive for dry and heat. (sunlight) When ivory turns yellow
than the best way is to put it is on a dark spot and it will turn
white again.

To clean you can use ethyl alcohol or acetone with a few drops of
ammonia. To polish ivory you use champagne-chalk for a good shine.
Broken ivory can be fixed with PVAC-glue or epoxy resin. When the
surface shows a lot of cracks, you can impregnate it with PVAC-glue
dilute solution. (soluble in water) To protect the surface you can
use almond oil.

In a nutshell, ivory is composed of both organic and inorganic
matrix with three main components: the mineral element
hydroxyapatite, the protein collagen and a ground substance that may
consist  of mucoprotein and aminopolysaccharides.  The morphology of
ivories are varied, each having characteristic markings depending on
the type of animal in which it comes from.  Substitutes, using
various synthetic and natural materials have also been formulated to
produce an ivory-like substance.   All of the above information has
been widely published.  A few titles:

    MacGregor, A. 1985.  Bone, Antler, Ivory and Bone.  Australia:
    Croom Helm Ltd.

    Maskell, A.O.  1905.  Ivories.  London.

    Thorton, J.  1981.  The structure of ivory substitutes In: AIC
    Preprints 9th Annual Meeting, Philadelphia, May 27-31, 1981, pp.
    173-181.

    Adhesives and Consolidants, IIC Preprints of the Contribution to
    the Paris Congress, 2-8 September 1994.
    (there are a few papers in this book with reference to ivories
    and related materials)

As for the conservation treatment, I do not suggest bleaching with
sunlight. The yellow coloration of ivory is a natural patina.  Other
colors may be produced intentionally or be an effect from a burial
environment.   Water or  water-based adhesives should be avoided,
as this may cause dimensional changes.  The adhesive or consolidant
selected should be compatible with the object, be reversible and not
change the appearance or color of the object.

Sara Moy


                                  ***
                  Conservation DistList Instance 15:30
                 Distributed: Tuesday, October 9, 2001
                       Message Id: cdl-15-30-007
                                  ***