Glass Facts You May Not Know

Did you know...

there are several types of glass?

glass is made from more than sand?

glass is made from secret recipes?

glass may contain gold?

you can see glass made?

There's More than One Type of Glass

Glass comes in lots of shapes and colors.  But, did you know, there are several types of glass?  The two common types of glass are soda-lime glass and borosilicate glass.  

For finished items that need to be very durable, borosilicate glass is used.  Think bakeware and laboratory equipment.  These items must be able to withstand thermal shock, or wide temperature ranges, often in rapid cycles.  If you've ever put a cold baking dish in a hot oven, you know what I mean!

Jars, drinkware, and window glass don't need to be quite so durable.  

Glass is made with a few other key ingredients

Glass made mostly from sand (silica) with a few extras that you may not know about. 

Soda (sodium oxide) is added as a stabilizer. Think eggs in a cake recipe.  It's a binder of sorts. Sand and soda need extremely high temperatures to melt. Lime (calcium oxide or carbonate) is added to reduce the melting point by almost 1000°F, from about 3000°F to around 2000°F!

Borosilicate has boron added to it to make it resistant to heat and chemical changes, like strong acids.

Other ingredients are added to change the colors, usually metals and metal oxides. Think iron and rust - related, but not the same.

Of course, each manufacturer has their own secret ingredients that they don't share with you and me!

Glass is Made from Secret Recipes

Each batch of glass is made of the raw ingredients: sand, soda, lime, and the secret ingredients.  Once
mixed, they are melted in a glass furnace at extremely high temperatures until molten.  Some glass is mixed by machine.  Hand-poured glass is removed from the furnace one scoop at a time and mixed by a highly trained glass-making artist.  If the glass needs multiple colors, each batch is made and then mixed on the metal table.  

Most glass is shaped by rollers, which give the glass it smooth or textured surface.  Some glass is mouth-blown into large cylinders, which are then opened and formed into sheets.  

Window glass is "floated", or poured onto a bed of molten metal, giving it that signature smooth finish.

Glass Colors Have Purpose

Sure, all the colors are pretty, but some go beyond aesthetics.  Amber glass block UV and blue light, making it a great option for medications, chemicals, and beer.  Blue glass blocks the UV and looks stunning - perfect for things that need some protection and a beautiful, attention-grabbing look.  Green glass protects less than amber and blue, but more than clear.  You'll find some wines in green bottles.

Glass May Contain Gold

Ever wonder why some glass is soooooo expensive?  Some colors are made with expensive ingredients!  Red and pink glass may be made with gold and purple might have manganese.  That beautiful cobalt blue glass... yep, made with cobalt.  Yellow, orange and amber glass might just have some sulfur in it.  You might find chromium in your green glass. There are loads more, but this give you an idea.

You Can See Glass Being Made

I've taken a few glass tours. If you have the chance, it's worth the time!  For a Colonial America experience, you can visit the Jamestowne Glasshouse, as shown in this photo by photographer Roger Green.  Kokomo Opalescent Glass and Wissmach Glass factories also offer tours. Contact them for details!

If you need a gift for those hard-to-buy-for occasions, check out my featured items here!

Until next time,

Ailsa

Want to know more? Check out these websites:

https://kog.com

https://fremontantiqueglass.com/

https://www.gpi.org/glass-coloring

https://www.sha.org/bottle/colors.htm

https://oceansidecompatible.com/pages/art-glass-terms

https://www.compoundchem.com/2015/03/03/coloured-glass/