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Black Sea Glass

On this page, you'll find out about:

• What is Black Sea Glass?
• Black Sea Glass - Rare? Is it Hard to Find?
• The Making of Black Glass for Black Glass Merchandise

From what we've researched, heard from others, and found through experience is that true "black" glass is almost impossible to find. 

Well, not impossible. Just very hard. We'll talk about why farther down the page.

What Is Black Sea Glass?

The term "black glass" (also called blackglass), as used frequently by sea glass collectors as well as collectors of bottles, insulators and some other old glass products, often refers to glass that APPEARS to be black. 

Here's an example of some "black sea glass" from Italy.

Black Sea Glass - Olive, Italy

This "Black" Sea Glass from Italy actually is a Very Dark Olive

The common name "black glass" is perfectly fine to use when referring to glass that appears to be black to the naked eye.

This very dark glass, though, when held to bright light, shows that it is actually colored.

This same sea glass from Italy appears black until held up to bright light, as Lin is doing here.

"Black glass" in many cases is a very dark olive green. However, it can also be a very dark shade of purple, red, blue, or brown.

In the next photos, the "black sea glass" is a somewhat lighter shade of green, which can be seen when the sun shines through it.

In normal lighting, this piece would be considered "black glass," while it's actually a dark shade of green.

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Buy the "Secret of the Sea" - Odyssey Sea Glass Poster by David and Lin 

Black Sea Glass - Rare?

"Black glass" of dark green or dark brown has in fairly common use for bottles for many centuries. However, these colors are somewhat rare to find in a sea glass collection. Why?

Well, for one very good reason at least - it's very difficult in normal lighting to tell the difference between a piece of very dark, frosted sea glass and the pebbles or rocks on the beach. Add some seaweed and shells and your eyes are going to have a a lot of fun trying to pick it out.

"Black" - Red and dark blue glass from England Durham by David

Much of the "black glass," or very dark glass, that ends up as tumbled, frosted sea glass was originally from bottles containing fluids that could be damaged by exposure to sunlight. This was most important one hundred years ago before refrigeration existed and before the "sophisticated" preservatives that are now widely used.

In many cases medicines and chemicals or even beer and wine had to be transported and stored for long periods of time in less than optimum conditions, and dark, thick glass was one of the best ways to insure conservation of the liquid the bottles contained.

(One of the biggest "black" sea glass producers were electrical companies, using a type of black material called vitrite (see more) for insulators.)

Summarizing this information, then, we can say that black beach/sea glass is fairly rare among collectors for at least these two reasons.

1. First, it is extremely hard to distinguish a tumbled black glass fragment from the other rocks on the beach, so what little there might be is likely to be overlooked.
2. Second, most black glass bottles were made before 1880. Ornamental or dishware black glass products (see below) make up only a tiny portion of production compared to bottles.

More About the Use of Black Glass in Bottles

Strength - Most of the old black glass bottles colors are due to a high concentration of iron oxide, either naturally found in the sand used, or added during glass production.

Some glass was made by adding iron slag, which produced a stronger glass more resistant to shattering; another reason for using black glass for bottles subject to harsh conditions in centuries past.

You might compare the strength of this "fortified" glass to some other glass colors. Colors such as blue, green, brown, and red were generally made by adding metals or combinations of metals. The strength of the glass was affected by how the metal used reacted with the other ingredients in the glass-making process.

*See more about this color at the Society for Historical Archaeology

From what we've seen, the very dark "black" sea glass is more resistant to breakage, and very dark colors (with the added iron slag, etc) result in finds of some pretty hunky old sea glass.

The Making of Black Glass for Black Glass Merchandise

The center for glassmaking from the 14th century was the island of Murano in present-day Italy, where many new techniques were developed. 

Murano became the center of a lucrative export trade in dinnerware, mirrors, and other luxury items.  Black glass was called obsidianus after obsidian stone.

Milk glass first made in Venice in the 16th century included black glass.

Influenced by the milk glass from Venice, Opaline glass was a decorative style of glass made in France from 1800 to the 1890s and colors included black glass.

Some Depression glass was black.  This was dinnerware and related glassware, not bottles. For example, this flower arrangement bowl.

Photo courtesy of www.retroartglass.com Black depression glass flower bowl.

Contemporary Fiesta ware (since 1986) included black glass.

See Warman's Depression Glass: Identification and Value Guide

Rhonda's Beautiful Patterned Black Sea Glass

Other general uses:

More Black Sea Glass:

Photos open slide show / Titles open original page

Identifying Dark Purple

Black Sea Glass is actually Green  

Is this Black Glass?

 

Dark Olive Or Black Sea Glass? 

 

Black or Purple Beach Glass

Identify - Black Sea Glass? 

LOTS of black sea glass 

Black Sea Glass found on New England Beach?

Singer Island, FL Beach Glass  

Galleon Beach Antigua Black Glass 

Black Sea Glass with a C 

Black Sea Glass? Identification 

Black Glass Bottle Top 

St. Croix, Virgin Islands, Black Glass

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