All projects are returned with an CD containing (1) a speadsheet with all analytical results, (2) graphics files of any figures that appear in your report, and (3) copies of any Adobe Acrobat files that were produced as part of your project (including the overall final report). For a downloadable sample of our reports, click HERE. Standard shipping (UPS, Fedex, or Certified/Delivery Confirmation mail) of artifacts and results is included with all projects.

To submit samples for XRF and/or obsidian hydration analysis, please use the Adobe Acrobat sample submission form provided by Northwest Research. Alternatively you can print out the web sample submission form, or we'll be glad to mail, fax, or email you a copy. All samples should be sent to the lab in Corvallis, Oregon. For additional details on sending samples to the lab for analysis, click on the How To tab at the top of this page.

The process of XRF trace element analysis is entirely nondestructive but is limited to obsidian and basalt artifacts with a minimum diameter of no less than about 10 mm and a thickness of no less than 1.5 mm. Larger specimens are preferred for analysis and should be selected whenever possible.

When a surface of freshly-flaked obsidian is exposed to the air, water is slowly absorbed into the surface of the artifact, leaving a narrow hydration rim that is visible under a microscope. The thickness of the rim depends, in part, on the age of an artifact, and provides researchers with the opportunity to directly determine the approximate age of its manufacture.

As is visible in the image above, the process of slide preparation is slightly destructive. A thin slice of glass is first carefully removed from the edge of an artifact. This thin wafer is fastened to a slide, ground to a thickness of about 30-50 microns, and is examined with a petrographic microscope. The hydration rim that has formed on the surface of the artifact can then be accurately measured to a precision of approximately +/- 0.2 microns.