How to Submit Samples

what follows is a general checklist of what to include with the specimens you submit,
along with answers to questions which may arise as you are preparing to send your samples.

what to include with samples

Include a cover (transmittal) letter, providing any pertinent information about the site or project which might be useful in interpreting the results. In the letter, please provide (if applicable) the project name, account, or job number as you would like this information specified on the invoice.

Please send two location maps; a vicinity map showing the general area in which the site or project is located (see Example of Vicinity Map), and a location map providing more detail with the site(s) locations plotted. This latter map could be a xerox of a portion of a U.S.G.S. quadrangle sheet, or a map of comparable scale already prepared for your project report (see Example of Location Map). Send UTM grid coordinates information also, but maps are very important for orienting students whom I occasionally retain to put information in database files.

preparing each specimen for analysis

Because x-ray fluorescence is a near-surface technique (the x-ray beam penetrates a short distance into the surface of the sample) results can be effected by the presence of surface contaminants. Such contaminants can be natural (e.g. adhering desert varnish, calcium carbonate precipitates, surface dirt) or "cultural"(e.g. inked catalogue numbers). To avoid "cultural" contamination problems, it is best to submit samples WITHOUT catalogue numbers written on them. While not all written-on catalogue numbers are problematic, lab personnel have the habit of using the smoothest, flattest surface of the artifact to apply the catalogue designation and, by unhappy coincidence, this is the surface that is most often optimal for directing the x-ray beam. If the catalogue number is written on the "best" surface for edxrf analysis, the number must be removed. It is much more cost-effective if such removal happens BEFORE the sample reaches the lab. It is sometimes not possible to avoid some natural surface contaminants (e.g. desert varnish, calcium carbonate pecipitates), but it is advisable to subject each specimen to a simple rinsing in distilled water prior to shipment.

Place each specimen in its own zip-loc bag, write the site number and catalogue designation on a slip of paper, and put the slip of paper inside the bag with the specimen. The site designation and catalogue number will be used to identify individual specimens in the xrf letter report (see How Will I Receive the Results?).

how to ship the specimens

There is no "best" way to ship. We've all heard, or repeated our own, horror stories about damaged or lost mail. While the U.S. Postal Service (USPS) has its share of such stories, other carriers (like FedEx, UPS, Airborne Express) are far from blameless. I have been satisfied with the USPS over the years and would recommend that you send your samples via first class (or priority) mail.

If you are concerned about a greater level of accountability, use the USPS Delivery Confirmation tracking option. Delivery Confirmation for first class mail costs about 50 cents, and buys a whole lot more than that in peace-of-mind. If you prefer other carriers (i.e. non-USPS), that's fine, but because GRL is located in a comparatively rural area it is quite safe to send specimens without using the signature-required delivery option. Signature-required submissions actually may take longer to arrive at the lab depending on how my schedule meshes with that of the delivery folk.

where to send the specimens

Send the specimens to: Dr. Richard Hughes, Geochemical Research Laboratory, 20 Portola Green Circle, Portola Valley, CA 94028-7833.

For further information contact: Dr. Richard E. Hughes
Telephone: (650) 851-1410

E-mail address:

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