How do you calculate appreciation of oriental rugs?

First off, oriental rugs should not be purchased for investment purposes. Buy what you like and treasure what you have. A well-cared for rug may last up to a century. Anyway, the following factors are used by an oriental rug appraiser: 1.value cycles of the present day market (supply & demand) 2. authenticity and most importantly, 3. the quality of craftsmanship or lack of it.