Ancient Glass Blog of The Allaire Collection

Early Roemer

Posted in Uncategorized by Allaire Collection of Glass on September 29, 2016


The restored ovoid bowl on this early Roemer is attached to an open stem decorated with pulled prunts. This Roemer bowl is more flared than example 40E. Unlike later Roemers there is no spiral foot only a pinched “toed” base ring. This form is closer to the Berkemeyer example 12E, which has a flared bowl. The discoloration on this early Roemer is due to the soil where it was found.

 H: 10 cm

16th Century

Ref: Henkes #45.13,Glass V&A #42,Ritman Coll. #20

56E Early Roemer 16th Century H 10cm

56E Early Roemer 16th Century H 10cm


Posted in Uncategorized by Allaire Collection of Glass on September 25, 2016




Roman Empire, Syrian-Palestinian area │ 4th century AD
Size: ↑ 10,4 cm; Ø max. incl. side-handles 5,3 cm; Ø rim 4,0 cm. │ Weight: 63 gram

Technique: Free blown. Tooled.
Classification: Stern (2001) type I, class C2a.
Description: Transparent very light green glass; handles very dark purple, nearly black glass. (See Remarks.) Two tubular compartments made from one single free blown tube, pressed in from the sides to form a diaphragm. Under right compartment remainder of pontil mark. Rim folded outward, upward and inward. On each side a handle on the body, drawn up angular and attached to the body and the rim.
Condition: Intact.
Remarks: Sometimes Roman glass seems to be black like the handles of this double balsamarium. In reality Roman glass is never black. With the help of very powerful light you can see the real colour: very dark green or very dark brownish green or (in this case) very dark purple.
The function of a double balsamarium is the following. One compartment was used to store black galena powder, while the other was for making this with a spatula into a cosmetic pasta. The people in the Eastern Empire used the pasta to outline the eyes in black to protect them against the sharp sunlight and the irritating flies.
Provenance: 1998 – 2010 Private collection of P.E. Cuperus, Laren (NL), no. PEC022.
Before 1998 in the private collection of C.A. Hessing (NL).
Published: A collection of Roman glass (Cuperus, 2009).
Reference: Roman and Pre-Roman Glass in the Royal Ontario Museum (J. Hayes, 1975), no. 359; Ancient Glass at the Newark Museum from the Eugene Schaefer Collection of Antiquities (S. Auth, 1976), no. 482 en no. 483; Antike Glãser – Staatliche Kunstsammlungen Kassel (M. Boosen, 1984), no.147; Montreal Museum of Fine Arts, Collection of Mediterranean Antiquities, Vol. 1. The Ancient Glass (B. Caron & E. Zoïtopoúlou, 2008), no. 137.


Posted in Uncategorized by Allaire Collection of Glass on September 22, 2016



At The Met Fifth Avenue, September 26, 2016–January 8, 2017

Exhibition Overview

This exhibition will illuminate the key role that the Holy City played in shaping the art of the period from 1000 to 1400. While Jerusalem is often described as a city of three faiths, that formulation underestimates its fascinating complexity. In fact, the city was home to multiple cultures, faiths, and languages. History records harmonious and dissonant voices of people from many lands, passing in the narrow streets of a city not much larger than midtown Manhattan. This will be the first exhibition to unravel the various cultural traditions and aesthetic strands that enriched and enlivened the medieval city.

Over 200 works of art will be gathered from some 60 lenders worldwide. Nearly a quarter of the objects will come from Jerusalem, including key loans from its religious communities, some of which have never before shared their treasures outside their walls. Jerusalem 1000–1400: Every People Under Heaven will bear witness to the crucial role that the city has played in shaping world culture, a lesson vital to our common history.   This link is to Met’s web site on show. Don’t miss the Featured Media videos on this in this web page. 

Below are pictures of the glass objects found in the exhibition:

Additional objects from the exhibition


Posted in Uncategorized by Allaire Collection of Glass on September 19, 2016


The Musee d’Art & Histoire Saint-Denis

Saint-Denis was a Gallo-Roman village north of Paris in the 2nd Century. During the Middle Ages it rose to prominence and in 1144 a new church was consecrated the Saint-Denis Basilica the first example of Gothic Architecture.  In the 17th Century the Basilica was excavated which turned up vestiges of the Middle Ages and Roman times.  The Musee d’Art & Histoire of Saint-Denis had a show in 2007 on some of these artifacts. We were there on the last day of the show and some of the artifacts have not be on display since.  What also makes this show interesting is that all of the material was found locally.


Posted in Uncategorized by Allaire Collection of Glass on September 16, 2016


The Château d’Écouen, in Écouen, north of Paris which today houses the National Museum of the Renaissance (opened in 1982) was built between 1538 and 1555 as commanded by Anne de Montmorency, an extremely wealthy and influential advisor to François the First, king of France. Today, as well as offering the opportunity to observe this impressive example of 16th century architecture, the museum displays collections of the Musée de Cluny comprising Renaissance objects including paintings, sculpture, textiles, furniture, metalwork and glass.

The glass collection is excellent, comprising mainly Venetian, Facon de Venise, and Spanish examples from the 16th and 17th Centuries. Click on the pictures to enlarge them and use Esc to get back to this page.


Posted in Uncategorized by Allaire Collection of Glass on September 14, 2016

Roman Glass Exhibition in Heerlen, Holland


An exhibition of Roman glass will be at the Therman Museum in Heerlen from April 29th until August 28th 2011.  Heerlen is a city in the southern part of Holland, close to the border of Germany.  The Museum derives its name from the ruins of a Roman bathhouse on which it stands. This location is an ideal place for this event which consists of almost 300 glass objects drawn entirely from private collections.  The objects are arranged around themes such as tableware, packaging and transport, and bathing.  Several rare objects will be included in the exhibition such as a beaker with four panels showing mythological figures, an opaque glass bottle with the image of the Greek warrior Ajax and the most important piece in the show a glass jug made by the master glassblower Ennion.  Accompanying the exhibition is an illustrated book with about 200 photographs by Tom Haartsen. Web site for museum:

Below are overviews of exhibition, the glass photos in the book are wonderful:


Posted in Uncategorized by Allaire Collection of Glass on September 10, 2016


(The following link will take you a procedure for cleaning weathered archaeological glass)

Weathered Archaeological Glass By Astrid van Giffen The Corning Museum of Glass

Glass is found at archaeological excavations in a variety of conditions. The glass condition can range from pristine, where no deterioration is visible, to so heavily degraded that practically all the glass has been transformed into corrosion products. The deterioration of the glass surface is generally known as weathering and the deteriorated area as a weathering crust.

The corrosion process

The chemical and physical properties of the burial environment and the composition of the glass itself are the main factors that determine the rate of deterioration of glass in the ground. Too little silica and more or less than the optimum 10 % of lime are especially detrimental for the stability of a glass. Soda glass is almost twice as stable as potash glass. However, under the right conditions any glass can show signs of deterioration.

In general, glass found in dry soils is in better condition than glass found in moist soils. This is because water is the primary cause of deterioration of glass. The exposure of glass to moisture causes alkali ions in the glass network to be slowly leached out and replaced by hydrogen ions from the water. This leached layer is referred to by several different terms: alkali-deficient layer, silica-rich layer, or hydrogen glass. It usually occurs within a few years of burial. Interestingly, it re-occurs in a cyclic manner, with additional layers being formed again, every few years. Distinct layers can often be seen, and as they build up, the weathering crust gets thicker and thicker. The final crust can vary in thickness from microscopically thin to so thick that it can easily be seen without a microscope. Frequently the leached crust is found to have a laminar structure with individual parallel layers ranging in thickness from less than 1 μm to about 25 μm. “The laminated structure can cover all the fragment homogeneously or it may start at one single point on the surface, which leads to circular patterns.”1 In some cases the alkali-deficient layers protect the remaining glass from further deterioration, or slow down the access of water to the glass and thus slow down the formation of new layers. Whether the crust is protective or not depends primarily on the composition of the glass and the pH of the leaching solution. In alkaline environments the silica network is attacked, eventually causing the total dissolution of the glass.

Although the chemical processes of glass deterioration have been extensively studied, they are not yet entirely understood and cannot be predicted. It is not clear why glass often decomposes in layers.

One theory for the laminar structure of weathering crusts is related to the glass’ contact with moisture. After the initial stages of attack, the leached layer is believed to partially transform into a new structure called silica gel, which is more porous than the leached layer. The porosity of the silica gel “provides a matrix in which subsequent precipitation and crystallization reactions can occur.”2 The parameters that influence the formation of silica gel and the reactions that occur within it are still being studied.

Another theory states “that as large sodium or even larger potassium ions are replaced by protons the physical stress on the structure causes the surface layer to split.”3 This allows water to get through to the fresh glass underneath and the process is repeated. The decrease in volume caused by the leaching of ions can lead to micro porosity of the surface layer, which in turn might cause the weathering layers.

It has also been suggested that the layering is caused by periodic or cyclic changes, such as seasonal variations in temperature and rainfall.4 Because such changes occur in yearly cycles the number of layers should be an indication of how long the degradation has been in process, similar to counting growth rings in a tree trunk to indicate the age of the tree. Several examples of glass with a known burial date support this theory. However, for the majority of objects the number of layers does not correlate to the estimated number of years of burial. In addition, layered weathering crusts have been produced in burial environments as well as in controlled unvarying laboratory conditions, in some cases in as little as 6 weeks. If the theory can be applied to date archaeological glass, it can only be used on a small fraction of them, most likely “those ranging from the early eighteenth century back through the medieval period. Roman and Byzantine glasses are generally too resistant to become heavily weathered; Egyptian glasses are most often found in arid environments, and therefore have not suffered much from corrosion; Mesopotamian glasses are often so heavily weathered that no glass remains, and what does is too

Visual appearance of deterioration

The deterioration of weathered glass can have an extensive variation of appearances. The visual effects of degradation most commonly found on excavated glass are dulling, iridescence, opaque weathering, a total loss of glassy nature, pitting, cracking of the surface, and discoloration.

Dulling refers to a loss of original clarity and transparency that is quite distinct from haziness caused by scratches or stains. It is closely related to iridescence, which is a rainbow-like effect on the surface of the glass similar to a thin layer of oil on a water surface. Both are caused by changes in the composition of the surface of the glass altering the refractive index. The weathering crust is made up of many thin layers leading to the iridescence, which is caused by “the interference between rays of light reflected from thin alternating layers of air and weathered glass crusts.”

Opaque weathering also has a laminar structure, but has a much larger number of layers. “The layers may be adhering to one another and may penetrate the entire surface or they may be laminating and superficial.”  This type of weathering is characterized by opaque areas, usually white, on the surface gradually eating deeper into the glass, and is generally referred to as opalescent weathering. At more advanced stages the color can be black or brown or even a mottled polychrome. The incipient stage is sometimes referred to as milky weathering because of the small spots or streaks of white. At the most extreme stage it is termed enamel-like weathering and is present as a thick covering varying in color.

Pitting can occur when the corrosion “eats” its way into the glass from a starting point either on or just below the surface, sometimes creating concentric circles around the starting point. When the weathering is lost, a hole or pit is left in the surface of the otherwise undamaged glass. Pitting often occurs simultaneously at individual sites throughout the surface of a fragment. Weathering from individual starting points can later grow into one another.

Shrinkage of the alkali-deficient layer, due to temperature and humidity changes, can cause cracking of the surface and within the weathering crust itself. Often the cracking does not become visible until some-time after the glass has been excavated. This is especially true for glasses buried in wet soils.

Discoloration of the glass can be found in combination with any of the above mentioned types of weathering and is caused by the migration or alteration of coloring ions and other trace elements. The ions can be leached out of the glass network or be taken up by glass from the environment. Iron and manganese cause the weathering crusts to blacken and contact with copper corrosion products can cause green staining. Certain ions, most notably manganese and copper, may change color through oxidation.

Combinations of several of these manifestations of glass deterioration are usually found on a single object. The extent of the degradation can also differ from one area on an object to another.

The thickness of the weathering crust can vary greatly, depending on the chemical stability of the glass and the aggressiveness of the burial conditions. In extreme cases corrosion products may have completely replaced the original glass. Underneath the weathering crust the so-called glass core retains the original composition and color of the glass.

Importance of preserving the weathered surface

Preservation of surface details is not the only reason to ensure that the weathering remains whole. The removal of weathering often reveals a very irregular and often pitted surface because air bubbles and debris trapped in the glass during production are exposed as a result of the degradation. The exposure of such a surface can result in misinterpretation of the original appearance of the object and is aesthetically unappealing.

Finally, there is the aesthetic appeal of the weathering itself, especially iridescence, which has become so associated with archaeological glass and is much valued for its beauty.

By Astrid van Giffen for the complete text with picture illustrating the different appearances please follow this link


Posted in Uncategorized by Allaire Collection of Glass on September 7, 2016



June 3, 2016 to March 26, 2017

RGM, Cologne – a center of ancient glass art

At the center of this exhibition is the impressive glass collection (world’s largest) of the Römisch-Germanisches Museum from the 1st to the 7th century.   In addition, the show will present outstanding finds from Cologne which, from the 18th century on wards, were sold to museums worldwide. Other glass finds are presented in the context of Roman and Frankish burial customs and religious concepts. The exhibition will also take a look at the raw materials and technical skills of ancient craftsmen. Link to RGM web site. To see more of this fabulous glass collection then below please follow this link to the museum study galleries also on this blog. This is active link to a book about this show and their glass collection.

Below are highlights from this show.

Additional post with pictures from the Römisch-Germanisches Museum:




Posted in Uncategorized by Allaire Collection of Glass on September 5, 2016

This is an American cobalt blue glass footed bowl. The beauty of this glass bowl is in the rich cobalt blue color and clean lines of its shape.

H: 4 inches


65A American Cobalt Bowl 1780-1800

65A American Cobalt Bowl 1780-1800

This American bowl (1780-1800) is very similar in style and shape to a dark green wald glass beaker (1500-1550) and points to how art repeats itself time after time.

65A American Cobalt Bowl 1780-1800

65A American Cobalt Bowl 1780-1800

86E Medieval Wald Glass Beaker

86E Medieval Wald Glass Beaker

Poison Bottle with Hobnail Pattern

Posted in Uncategorized by Allaire Collection of Glass on September 3, 2016

Poison Bottle with Hobnail Pattern

This poison bottle is in the shape of a half pint Pitkin made using the half post method.  Unlike some poison bottles it is made of colorless glass and has no embossed words on it.  The only distinguish characteristic that makes it a poison bottle is the hobnail pattern.

H: 4 ¾ inches


47A Poison Bottle

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