Patination and Historic Bottles
The internal and external surfaces of a glass bottle that has been buried (probably a majority of collectible bottles) will usually react variably to the natural chemical processes of decomposition in both water and the earth. This process of weathering is called “patination” in the archaeological world (Jones & Sullivan 1989). The results of this decomposition is a crust or other glass surface alteration with is also referred to as a “patina,” “sick glass,” or simply “stained” glass.
The term sick glass is descriptive in that the glass is sick, i.e., it is very slowly dissolving (Munsey 1970). This effect is also called – particularly by collectors – as “opalized,” “iridescence,” or “opalescence” (Tooley 1953; Kendrick 1963). There seems to be no one term that is widely accepted, although I generally refer to it as patination or staining on my Historic Bottle Website.
As examples, the two 1860s-era green soda/mineral water bottles from San Francisco, CA. (images #1-3) show the difference between a moderately stained bottle (left bottle in image #1 & image #2) and an unstained similar example (right bottle in image #1; close-up in image #3). The stained bottle (embossed D. S. & Co. / SAN FRANCISCO and dating from 1861-1864 [Markota 1994]) has a dull, semi-opaque, and relatively unattractive surface to the glass – all undesirable attributes to collectors. The unstained example (embossed PACIFIC / SODA / WORKS – CLASSEN & CO / SAN / FRANCISCO and dating from 1868-1870 [Markota 1994]) is glossy, clear (not semi-opaque), and esthetically more pleasing to the collector’s eye. In near perfect (unstained, undamaged) condition, both bottles are $75-$100+ items. However, the stained example is probably only worth $50 or so in its current condition. (Bottle values and patination are discussed more below.)
The various types of patination
Staining or patination is highly variable and unpredictable. Although glass is a highly resistant substance, it is still subject to slow corrosion by water and environmental chemicals. This is a function of the specific composition of the glass as it relates to the chemistry of the soil and water that the glass resides in, as influenced by amount of exposure or contact time (Munsey 1970).
Patination is more common in bottles with a high soda (and low lime) content. Water will gradually dissolve or leach out the soda component of the glass, leaving a coating of sodium carbonate and eventually silica behind. This process continues year after year, resulting in a buildup of very thin layers, like the rings of a tree (though without the dating opportunity that tree rings allow).
Particularly susceptible bottles or those that have been in contact with water or soil for a very long time (e.g., a 2000-year-old Roman bottle) will exhibit pitting, which is the extreme corrosion of the glass surface. (See image #4 -a 1900-year-old Roman bottle with surface pitting.) Eventually glass will corrode completely away in any environment given enough time (Kendrick 1963; Elliott & Gould 1988).
Patination & collector value
Staining or patination is not a reliable indicator of age, but bottles with high soda content – particularly machine-made items – will stain faster than those with less soda. Black glass and some other types which are apparently low in soda and high in lime will weather for a hundred years or more with little change to the glass surface (Kendrick 1963). Staining is often accelerated on bottles in contact with ashes and alkaline soils and almost non-existent, of course, with bottles that have never been buried, though even those bottles, if given thousands of years, would likely patinate.
One notable exception to the “never been buried” concept is that bottles retaining the original contents for a long period will, over time, usually experience a reaction between the internal glass surface and the contents that results in a milky “content staining” on the inside of the bottle.
Patination is usually considered desirable in many classes of antiques, if for no reason other than as an indicator of true age and authenticity. Patination can also enhance the “look” of many antiques like furniture, scrimshaw, and other items. With antique or historic bottles, however, most forms of patination are usually not a desired feature and can significantly impact value, although the effect on value is highly variable…sometimes it is desired. (For more information on patination in other classes of antiques and collectibles, see Douglass Moody’s excellent WorthPoint article on the subject: http://www.worthpoint.com/blog-entry/patina-indicator-age-or-not)
As an example of patination on a bottle being desirable, consider the amber bottle in images #5 (entire bottle) and #6 (close-up). This is an early 20th century, machine-made, export style beer bottle used by (and embossed with) the A. GETTLEMAN / BREWING CO. / MILWAUKEE (WI.), which was in business from 1887-1961 and then became part of the massive Miller Brewing Co. This bottle – which dates from the 1910 to 1919 (National Prohibition) – exhibits the colorful and quite esthetic type of rainbow patination that collectors refer to as opalescence or iridescence. These colors are a result of the way light waves are broken up by the layers of corrosion and reflected to the eye (Munsey 1970).
The patination of this particular bottle is a result of its unique glass composition (unknown) and reaction to the alkaline (basic) soils in Arizona, where this particular bottle was excavated. Being machine-made, this bottle would generally receive minimal interest from collectors (i.e., a value of no more than about $10). However, with the lovely patination – what some collectors call “nature’s Tiffany” – the value could be $20-30+.
Another example of an esthetically pleasing patination is the bottle pictured in images #7 and #8. This bottle is embossed with ROGERS / NURSERY / HAIR LOTION and is possibly English in origin, though this particular bottle was found in one of the earlier (late 1860s) central Nevada gold camps. This bottle exhibits a spectacular profusion of blue, gold, green and purple iridescence depending on the light and holding angle of the bottle. This is probably only a $10-15 item in near “mint” – non-patinated – condition. With this level of desirable rainbow patination, the bottle is likely worth at least twice that amount.
When patination lowers bottle values
On the other end of the spectrum are the large majority of stained bottles whose the value is diminished by esthetically displeasing patination. The bottle pictured in images #9 (entire bottle) and #10 (close-up) has a more common type of patination – a milky white, opaque coating – that justifies the term “sick glass.” This particular bottle is embossed with C. CONRAD & COs. / ORIGINAL / BUDWEISER and hails from St. Louis, MO.
The product was widely shipped throughout the country as the first commercially pasteurized, bottled beer. These early export beer bottles date from between 1876 and 1882 (Toulouse 1971; Lockhart pers. comm. 2004). This type of staining is very common on the outside and inside surfaces of bottles that have been buried. One of these bottles in near “mint” condition is a $75-$125 item; the pictured example would have a value of about half to two-thirds that range.
Images #11 and #12 show a large chemical or ammonia bottle that has moderate to heavy staining on both the internal and external glass surfaces. This bottle would have minimal value regardless of whether it is in mint or stained condition, since it has no embossing and is a very common general bottle shape. As is, this bottle is of almost no value even though it dates from the 1875-1885 era.
It must be noted that bottles with staining or patination can be mechanically polished to restore the glass surfaces to a more or less original look. This is commonly done with historic bottles usually but not always enhances the value, and is something that collectors need to be aware of. That, however, is the subject of a future WorthPoint article…
There are no firm rules as to how much bottle value is diminished (or enhanced) with the presence or absence of patination. All things otherwise being equal (i.e., the bottle is physically undamaged), the value effect is dependent on the density and type of staining, the rarity or commonality of the specific bottle (very rare and desirable items may be little affected), the likelihood of the bottle responding well to mechanical cleaning, the level of pitting (if present), and many other factors.
On average, this author would guess that the average bottle with average undesirable staining is probably diminished in value by at least 15-25%. The value of historic bottles is a very complicated and slippery subject in which staining is only one element in the formula and all of which are the subject of future articles.
For more information on the subject of historic bottles – including the terminology used in the above descriptions – please consult my Historic Bottle Website (HBW) at: www.sha.org/bottle/index.htm The references noted in this article are found on the HBW’s References page at this link: www.sha.org/bottle/References.htm. For viewers unfamiliar with some of the terminology used in this article, please see the HBW’s Bottle Glossary page at www.sha.org/bottle/glossary.htm.