Here is a further explanantion of why the "de minius" exemption was created, according to the American Society of Appraisers:
What types of items are likely to qualify for the de minimis exception? When we proposed the 200-gram limit we had a particular suite of items in mind. The following types of items may qualify for the de minimis exception: many musical instruments (including many keyboard instruments, with ivory keys, most stringed instruments and bows with ivory parts or decorations, and many bagpipes, bassoons and other wind instruments with ivory trim); most knives and guns with ivory grips; and certain household and decorative items (including teapots with ivory insulators, measuring tools with ivory parts or trim, baskets with ivory trim, walking sticks and canes with ivory decorations, and many furniture pieces with ivory inlay, etc.). However, to qualify for the de minimis exception, all of the above criteria must be met (either A or B and CG).
What types of items are not likely to qualify for the de minimis exception? Examples of items that we do not expect would qualify for the de minimis exception include chess sets with ivory chess pieces (both because we would not consider the pieces to be fixed or integral components of a larger manufactured item and because the ivory would likely be the primary source of value of the chess set), an ivory carving on a wooden base (both because it would likely be primarily made of ivory and the ivory would likely be the primary source of its value), and ivory earrings or a pendant with metal fittings (again both because they would likely be primarily made of ivory and the ivory would likely be the primary source of its value).
How do I demonstrate that my item meets the criteria to qualify for the de minimis exception? To qualify for the de minimis exception, an item must meet the criteria provided above. We consider an item to be made wholly or primarily of ivory if the ivory component or components account for more than 50 percent of the item by volume. Likewise, if more than 50 percent of the value of an item is attributed to the ivory component or components we consider the ivory to be the primary source of the value of that item. Value can be ascertained by comparing a similar item that does not contain ivory to one that does (for example, comparing the price of a basket with ivory trim/decoration to the price of a similar basket without ivory components). Though not required, a qualified appraisal or another method of documenting the value of the item and the relative value of the ivory component, including, information in catalogs, price lists, and other similar materials, can also be used. We will not require ivory components to be removed from an item to be weighed.
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