History in Your Hands

What is Genuine Sea Glass and Sea Pottery?

Naturally produced “genuine sea glass” originates as pieces of glass from items such as drinking bottles, vases, medicinal bottles, tableware, perfume bottles, jars and so on. It was common practice in centuries past to simply discard one's rubbish into the sea because the currents carried it away. Spending decades being tossed around with the currents and tides, these shards undergo a cycle of being dragged over sandy sea bottoms and bashed against rocks. The end results are naturally polished smooth nuggets of sea glass with a characteristic frosted appearance. What was once a man-made product has now been refined and transformed by nature! 
 

Sea Pottery begins its journey as pieces of porcelain, china and ceramics and follows a similar process as sea glass. Over time the corners round from the waves and rocks and the color palette slowly fades. Sea pottery can be tricky to date and identify due to this loss of color, but one can’t deny certain notable features such as the pagodas of the Blue Willow or the embossed surfaces of Queensware by Wedgwood.

 

SO JUST HOW OLD IS MY SEA GLASS?

While sea glass rarity and value can vary depending on where it is found, many of the pieces in our collection, including our sea pottery, likely date as far back as the early 19th century. This includes colors that have not been manufactured or used commercially for quite some time, making them all the more rare. It is important to note that often colors can vary widely in perception depending on differing lighting situations (I.e. indoor fluorescent, LED, incandescent, natural sunlight). 

Additionally, terminology used to describe sea glass colors and the almost infinite color variations has never been officially standardized. So, what does this mean? Often you will see variations of a particular shade that are all titled the same but are quite different in hue. This is especially true when classifying green and amber shades. 

The main components of glass are sand (silica), soda (sodium oxide), and limestone (calcium carbonate). Ironically, clear or 'colorless' glass was the goal of many glassmakers in centuries past, but to achieve this was no easy feat. It required the use of the purest silica commonly found in sand and impurity free decolorizing additives. Variations in glass colors were achieved by the addition of minerals and additives and A LOT of trial and error. However, these formulas were closely held glassmaker secrets!  

When determining the value of a piece we look at the following:

  1. Color/Geographical Location: Is the piece a common color to find or is it more rare based on location? Our pieces are collected from the United Kingdom unless otherwise specified in the product description. The majority of our sea glass is found near the sites of old bottleworks factories and Victorian dumping grounds. While some colors can be found in abundance in one area it may be rare and scarcely found in another!
  2. Size/Shape: The more round the glass is, the older it tends to be. Jagged and shiny edges generally mean the piece is newer.
  3. Patterns/Markings/Bubbles: Thickness of the piece as well as signs of bubbles encased within the glass indicate an older piece.
  4. Quality of Frost: A heavier and smoother frosting indicates age. *We always apply a light coating of mineral oil to enhance the color of our sea glass and dull the frosting. To restore the natural frosting simply wash your sea glass lightly with soap and water and a soft toothbrush. 

SEA GLASS COLORS AND RARITY

Whites / Off-Whites / Browns / Kelly Greens

The most common colors of sea glass to find along the shoreline are shades of white, brown, and kelly green, although even these are limited. Many of these pieces come from soda and beer bottles as well as glass food containers and medicinal bottles during the early to late 20th century, although these colors are still widely used today. Air bubbles trapped within the glass, thickness, and any identifiable patterns or markings can also indicate that you've found an older piece of glass in these shades. 

Light Ambers

Originating from bottles for whiskey, medicine, spirits, and early bleach containers, amber glass has the ability to block sunlight and protect the contents. Due to this amber was, and still is, the most common color for beer bottles as it prevents beer from becoming “light struck” which causes a distinctive off-flavour. Generally, the lighter shades of amber such as golden amber or honey are considered the rarer of all the brown shades of sea glass. Some amber sea glass shards are as old as the early 1900s when whiskey, snuff and bitters bottles were commonly available in this color.

 Seafoam Blues & Greens

Seafoam sea glass comes in many subtle variations of blues and greens as a result of the iron impurities found in most sands during the glass making process. Many of the pieces in our collection are from the early 19th century where they were commonly used in round bottom, torpedo and codd bottles designed for carbonated beverages such as soda and mineral water. These pieces are generally quite thick and contain air bubbles. After 1920, these shades were more scarcely used as merchant bottle users wished their products to be more visible to the buyer and opted for clear glass. However, seafoams continued to be used in Coca-Cola bottles.

Olive Greens / Yellow Greens

Olive green and yellow green sea glass derives from bottles used for wine and champagne, mineral water, snuff, medicines and occasionally perfumes. In general, the darker the shade the older the glass. These shades are very uncommon after about 1900 with minimal exceptions. Wine & champagne bottles that are still produced in these shades tend to have a "brighter" appearance than the subdued olive greens of the past.

Dark Aquas / Teals / Blue Greens

Blue green sea glass such as teal is quite rare and mostly derives from bottles and jars used for ink, mineral waters, baking soda, wine and possibly art glass manufactured between the 1870s and 1910s. These shades were very uncommon on machine-made bottles and generally denote a 19th or very early 20th century manufacture.

Cobalt / Sapphire / Cornflower / True Blues

Produced between the 1880s and 1950s, cobalt and sapphire blue glass were mainly used for poison and medicine bottles to distinguish them among other colored bottles. Additional uses were ink wells, perfume bottles, cosmetics and occasional food containers. Cornflower blue is one of the most rare shades of blue sea glass as far fewer cornflower blue items were manufactured.

Purples / Lavender / Lilac

A vast majority of purple-hued sea glass originates from Pre World War I clear bottles made with a manganese oxide or nickel additive. First used in the 1400s by Venetians to achieve a colorless glass, these additives produce varying shades of purple when exposed long-term to UV sunlight. Dependent on the amount of additives used colors might vary from lighter pinks and lavender to darker shades of purple. 

Pinks / Peach

Similar to purple shades, a good bit of pink or peach sea glass is “sun colored,” derived from clear glass bottles made with selenium as a decolorant. Peak production of true pink glass was during the Depression years between 1915 to 1950 where it was used in tableware known as Depression glass. Deeper and rarer hues of these shades often come from vases and perfume bottles.

Turquoise / Cyan / Sky Blue

 Turquoise and cyan are very rare finds dating back to the Victorian era were they were utilized in old electric glass insulators, vintage seltzer water bottles, old decorative stained glass and glass wares. Very little of these shades were made and none were mass produced.

Black

 Black sea glass, which tends to be very thick and old, dates back as far as the early 18th century where it was commonly used for beer and liquor bottles. Interestingly, black sea glass is actually not "true" black but a very dark olive green or a dark brownish amber shade when held up to the light. Because of the thickness and density of the glass, very little light passes through making the glass appear black. 

Grays

Most gray sea glass shards come from thick pieces of crystal tableware from the late 1800s to the early 1900s that contained amounts of lead oxide to enhance the sparkle. When exposed to the ultraviolet sun rays, this effectively turned the glass a darker color. Another source could be old glass television screens.

True Reds

 Red is one of the most sought after shades of sea glass and quite difficult to find as a very limited amount of red glass was ever mass-producedRed was a popular color for tableware, some bottles, and for utilitarian uses such as red warning lights (car tail lights, ship’s lanterns, railroad warning lights, etc.) as well as stained glass from the late 1800s through the 1940s. True red (ruby red) was produced with oxide of gold.

True Yellows

Yellow Sea glass begins as clear glass with a selenium additive that develops a soft yellow color when exposed to sunlight. Yellow sea glass is considered very rare as there were very few mass produced yellow bottles. Many of the pieces in our collection most likely originate from tableware and decorative art glass. 

Orange

Orange glass was hardly used for any forms of mass-produced glass. If you’ve found an orange shard of sea glass and it’s not Amberina (a combination of red and yellow or orange), it’s likely a shard from something designed during the art-deco period. Orange sea glass also comes from tableware, the edges of red warning lights, or Carnival glass.

Milk Glass / Opaque Glass

Most white opaque shards (often referred to as milk glass) come from tableware and wide-mouth cosmetic jars used in the 1950s and 60s. It can be challenging to date milk glass because it covers several different time periods. Milk glass also comes in pastel opaque colors such as lime green (Jadeite), creamy yellow (Custard Glass) and soft blue; however, white is the most common.

Multi-Colored

Multi-colored sea glass is truly a treasure to find as it can only be found in limited places around the world. Most of the pieces in our collection come from Seaham, England which is now famed for its glass making history. Victorian Era bottleworks factories churned out thousands of handblown bottles a day from the late 1800's to the early industrial era. When creating different colored glass, workers often inadvertently left small fragments in melting crucibles which eventually congealed into multi colored scraps that were discarded at the conclusion of the day.