Database handle for the object. It is of XML type ID, so is constrained to beunique in the XML document within which it occurs. An external identifier for the object inthe form of a URI may be constructed using standard XML and XPointer methods. This is doneby concatenating the URI for the document, a fragment separator, and the value of the idattribute.
A positive integer value that identifies the relative significance or importance of the constituent, with 1 signifying the highest rank. Using this attribute eliminates possible ambiguity when using abundanceCode to infer significance.
Source
<element name="Constituent" type="diggs:ConstituentType"><annotation><documentation>An object that describes minor constituents within a lithology zone.</documentation></annotation></element>