History

Tom Origer established Origer's Obsidian Laboratory (OOL) in 2002 after cofounding and directing the obsidian laboratory at Sonoma State University in 1979. OOL processes several thousand specimens each year from a variety of archaeological contexts, primarily in western North America.

Tom received his Master Degree in 1983 at San Francisco State University. His thesis focused on establishing hydration rates for two of California's North Coast Ranges obsidians: Napa Glass Mountain in Napa County and Annadel in Sonoma County. Tom and his staff have been involved a wide range of research projects that included analysis of obsidian specimens created by Ishi in the early 20th century to the 14,000+ years old occupations in Paisley Caves in south-central Oregon.

In the 1988, Kim Tremaine and Dave Fredrickson developed the concept of "comparison constants" used to show the relationship of hydration development on specimens from obsidian sources. Hydration was induced in the laboratory on specimens from two or more geochemical sources of obsidian, and the thickness of the hydration bands that developed were compared. By this method, it was possible to seriate obsidian sources with regard to their relative rates of hydration.  For example, of four common obsidian sources in California's North Coast Ranges, it was found that Borax Lake obsidian hydrated fastest, while Mount Konocti and Napa Valley (aka Napa Glass Mountain) obsidian hydrated at the same rate, but more slowly than did Borax Lake obsidian. Bringing up the rear was Annadel obsidian, which hydrated slowest of these four sources.

Because of Tremaine and Fredrickson's (1988) study and other more recent research, we here at OOL have been engaged in a long-term project where obsidian sources are visited and specimens collected so that hydration can be for induced on them. The goal is to develop a better understanding of the development of hydration on obsidian from each source thereby aiding development of site-specific and  regional chronologies based on relative and absolute dates derived from the obsidian hydration phenomenon.

To date, many dozens of obsidian sources in the western United States have been visited by OOL staff in California, Idaho, Nevada, and Oregon, and plans are being made to visit obsidian sources in other states. It should be mentioned, that this research has been completed thus far in a collaborative manner, in that obsidian samples have been collected and submitted by other researchers, for example, the folks at Far Western Anthropological Research Group in Davis California.

Reference

Tremaine, K. and D. Fredrickson
1988 Induced Hydration Experiments: An Investigation in Relative Dating. Materials Research Society Symposium Proceedings Vol. 123:271-278.  

Pricing

Standard Hydration
A standard thin section preparation and hydration band measurement with letter report

Rapid Turnaround*
Standard hydration for batches of less than 10 thin sections with an email report within 48 business hours of receipt of specimens*

Induced Hydration
Induced hydration on submitted specimens plus induced hydration of control specimens with a letter report that describes the procedures followed as well a table displaying the hydration band measurements.

*Please contact OOL prior to sending specimens for confirmation of schedule
 

Shipping Information

- Be sure to securely package specimens for shipment. If in doubt, use more padding so that the specimens are not crushed in transit.
- Each specimen should be shipped in its own ziplock bag or other container.
- If you desire that a specific portion of the specimen be analyzed, we suggest that your photograph the item, scan it, or photocopy it, and mark with an arrow the location you want analyzed. Remember, a single thin section can provide hydration band measurements for two or more facets (e.g., dorsal, ventral, and truncated surfaces).  
- Please provide a specimen inventory:  a hard copy with the specimens and a digital copy via email.
- Include a letter of transmittal with all necessary contact information.

Services

Standard obsidian hydration analyses that result in obtaining hydration band measurements.
Calendar dates can be provided for those sources where chronometric control exists. In order to calculate dates, we will need obsidian source information and the location of the site where the specimens were obtained.

Induced hydration studies that allow for comparison of the amount of hydration that develops on single source specimens as well as comparison of the amount of hydration developed on several obsidian sources processed simultaneously.
Induced hydration studies are especially valuable in that they reveal variation or homogeneity in hydration band development within and between obsidian sources.
Comparison constants from induced studies are particularly useful in establishing hydration rates for an obsidian source with no known hydration rate when it is compared to the hydration rate of a control source - for example, Napa Glass Mountain which has a well established rate.

Obsidian Hydration 101

Things to remember when sending in samples:

ID:  Each specimen should have a unique identifier, and be clearly labeled and bagged separately.
Catalog: List of specimens.
Size: Obsidian Hydration can be done on any size piece, however small specimens may be completely consumed in the process and if you plan to XRF source items, it is best to do so before hydration analysis (Especially on small items!)
Condition: It may be impossible or difficult to get readings off of specimens that have been weathered, sand blasted, or burned. Call if you have specimens in this situation to discuss options.
Sourced: Specimens can be read for hydration band measurements, but these numbers mean nothing in terms of dating the specimen without source data and location of the site! Please provide source and location data or call to inquire about our "visual sourcing" costs and capability for your project area.