Database handle for the object. It is of XML type ID, so is constrained to be
unique in the XML document within which it occurs. An external identifier for the object in
the form of a URI may be constructed using standard XML and XPointer methods. This is done
by concatenating the URI for the document, a fragment separator, and the value of the id
attribute.

A value that describes the method by which the lithology was
determined. Allowed values are: - inferred; estimated from some indirect
measurement such as elog - lab test; determined from laboratory analysis
(such as particle size - missing; method known but not reported here -
other; method other than the choices in this list. Further information
should be provided in the remarks property - reported; description comes
from a third party source - unknown; method of description unknown and
can likely not be determined - visual; description comes from visual
description of the material

<div>
  <h3>lang (as an attribute name)</h3>
  <p>denotes an attribute whose value is a language code for the natural language of the content of any element; its value is inherited. This name is reserved by virtue of its definition in the XML specification.</p>
</div>
<div>
  <h4>Notes</h4>
  <p>Attempting to install the relevant ISO 2- and 3-letter codes as the enumerated possible values is probably never going to be a realistic possibility.</p>
  <p>See BCP 47 at
    <a href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt">http://www.rfc-editor.org/rfc/bcp/bcp47.txt</a>and the IANA language subtag registry at
    <a href="http://www.iana.org/assignments/language-subtag-registry">http://www.iana.org/assignments/language-subtag-registry</a>for further information.</p>
  <p>The union allows for the 'un-declaration' of xml:lang with the empty string.</p>
</div>