Red is, indeed, both very rare and quite beautiful-- and it is perhaps this combination of scarcity and beauty that makes it particularly sought after. But just to "put the record straight," though-- Red is NOT "the rarest sea glass color." That said, it is commonly estimated that a beach comber will have to pick up between 3000 and 5000 pieces of sea glass to find one piece of red. In addition, red glass (due to its chemical composition) tends to be "softer" and more "brittle" than many other colors of glass, and thus even when a collector does find a piece of red, the piece is often quite small, and not necessarily in nice smoothly frosted condition.
So, what's the story with red glass?
For starters, red simply isn't a color that has been used very often, for commercial glassware. There are a couple of reasons for this: Red glass is costly to make, and difficult to work with. And, ultimately, "difficult to work with" also drives up the cost of making red glass objects.
As I have written in other posts, colored glass is typically the result of adding metals and minerals (in oxide and chloride-- powder-- form) to sand and silica mix that is glass before it is molten. The simplest way to obtain a medium to deep red glass color is by adding gold-- in powder form. And, at $100s per ounce, this has generally not been an economically viable proposition for glass manufacturers. As often as not, when we run into red glass in an antique store, it is more likely to be "art" glass than manufacturer production glass.
Because of the cost of using gold, alternatives have been explored. Most successfully, highly purified iron and cupric oxide has been used. However, new challenges arose.
Some years ago, I was proprietor of an art gallery, and one of our specialties was blown art glass from small studios and individual artists. In the course of ten years or so, I got to know a lot of glass blowers-- and often noticed the absence of deep red glass in their work.
Knowing that there were alternatives to using gold for red glass, I asked "why no red?" And learned that even though there are non-gold options to make red glass, they can only be used in extremely controlled furnace environments. The raw materials have to be extremely pure and highly processed-- and that quickly becomes expensive. One glass artist described red glass as "too temperamental," explaining that he could make a "pot" of red glass, but if the furnace got just 10 degrees too hot he'd "end up with brown soup." Keep in mind what it might take to calibrate in 10-degree increments in the context of glass having a melting point of 2700 degrees Fahrenheit. I also learned that red glass-- in its molten state-- is extremely corrosive and damages the "pots" used in the furnaces, meaning that they have to be replaced more often than when working with most other colors.
As an example (again, returning to my days at the art gallery), in 1987 major Finnish glass manufacturer iittala decided to commemorate the 50th anniversary of their world famous "Aalto" glass vase by making a special limited edition in deep red. The original intent was that the edition size was to be 1000 signed and numbered pieces worldwide. After extensive experimentation and numerous failures, the edition size was cut short to just one hundred pieces, due to "manufacturing difficulties."
As an interesting aside, red glass was often used as "tiny accents." For example, when I look at sea glass "objects" such as buttons or beads (which in and of themselves are rare to find), red is a relatively "common" occurrence. Perhaps a full one-quarter of the sea glass beads I have found have been red... but it's very much a "relative" thing, as the chances of finding any sea glass bead is maybe 1-in-2000! Although beads are not exactly rare, most are never picked up because of their tiny size-- beach combers see a piece of glass less than 1/4" in diameter and think "why bother?" not realizing that the tiny round piece has a hole through it, making it a miniature treasure.
|"Cranberry Glass" as sea glass|
The bottom line is that most sea glass-- probably 99% of it-- comes from commercial glassware. That is, glassware that "contained" something, and/or was "used" for something... after which its utility ended, and it was discarded.
Whatever its origins, red glass is definitely a "treasure" for a sea glass collector, as well as for the few jewelry artists who are bold enough to use it in their work.
To see more photos of red sea glass (and I have many!), please visit my Red Sea Glass Photo Album on Flickr.