Home Glass Chemistry Blending verses Mixing glass colors

Glass Blending verses Glass Mixing

Glass is a wonderful media to do art with. Making

marbles is one of the beautiful things one can do with

glass. Painting a picture is another beautiful thing one

can do. I want to explain the difference between

blending and mixing these two media.

Let’s look at paint color and mixing:

When a painter squeezes paint on a pallet, the person

may take a brush and pull paint from different colors

and mix them together to make a new color.

Here are just a few of the color mixing possibilities:

Red + Yellow = Orange

Yellow + Blue = Green

Blue + Red = Violet

Red + Orange = Red-orange

Yellow + Orange = Yellow-orange

Yellow + Green = Yellow-green

Blue + Green = Blue-green

Blue + Violet = Blue-violet

Red + Violet = Red-violet

All start with the basic red, yellow and blue as these

are the primary colors of paint.

When light passes through a prism, it separates into

the colors that make it up. White light changes to a

swath of colors. This rainbow is called a spectrum. You

can make spectra in many ways: with a prism, with

drops of water (as in a real rainbow), or with gratings.

When astronomers pass the light of a star through a

spectrograph, they get a spectrum of the star. The

spectrum looks like a regular rainbow of colors.

The human eye and brain together translate light into

color. Light receptors within the eye transmit messages

to the brain, which produces the familiar sensations of

color. This is how we see the colors of paint.

Now let’s look at glass color and blending:

Glass colors can be blended but not mixed like paint.

The blending of glass in a marble-making machine

may occur in the oven when the glass colors are

molten or as the stream first starts to hit the rollers

after being cut.

Think of magma, a molten substance below the Earth’s

crust. The journey begins in the mantle. Here some

red-hot magma is being pushed up towards the crust.

Some of this magma creeps into the cracks of a

volcano; while, the rest is forced out of the top of the

volcano. Once the magma is out of the volcano, it is

called lava. The lava cools and forms igneous rocks.

Then some of the igneous rocks roll down the

mountains formed by the volcanoes and eventually

end up in the ocean. As they roll, bits and pieces of the

igneous rocks are broken and form sediments. Layer

after layer of sediments are pressed and cemented

together forming sedimentary rocks.

Some of the sedimentary rocks on the very bottom get

hot because of the pressure and change to

metamorphic rock. When the metamorphic rock is

buried deeper, it gets hotter and melts. Once again, it

becomes magma and may eventually be pushed up

and out of a volcano.

The colors of the rocks were determined in the magma

state when first formed.

Glass is usually defined as every solid that possesses

a non-crystalline (i.e., amorphous) structure and that

exhibits a glass transition when heated towards the

liquid state. In this wider sense, glasses can be made

of quite different classes of materials: metallic alloys,

ionic melts, aqueous solutions, molecular liquids, and


Glass can be colored by using compounds from the

periodic table.

For example compounds colors:

iron oxides gives greens, browns

manganese oxides give deep amber, amethyst,


cobalt oxide gives deep blue

gold chloride gives ruby red

selenium compounds gives reds

carbon oxides gives amber/brown

mix of mangnese, cobalt, iron gives black

antimony oxides gives white

uranium oxides gives yellow green (glows!)

sulfur compounds gives amber/brown

copper compounds gives light blue, red

tin compounds gives white

lead with antimony gives yellow

As you can see, glass color is a chemical process from

elements from the periodic table and can be blended.

An experiment:

I took red, blue and white glass colored rods and did

an experiment with them. I cut them into two-inch

segments and made three marbles.

Marble #1:

I made glass powder out of six rods, 2 red, 2 blue and

2 white and made a marble. As you can see from the

picture, the glass muddied-up as powdered glass

always does regardless of the colors one tries. The

powdered marble was not able to neither go round nor

keep the orange peel look as the powder’s particles

are so small and the glass bubbles under even the

coolest part of the torch flame.

Marble #2:

Next I made small frit out of the six rods, 2 red, 2 blue

and 2 white and made the marble you see here. The

frit stayed true to the colors as I expected. No blending

since I didn’t make and twists or turns to stretch the

glass colors to appear as if they were blended.

Marble #3:

Finally, I took the six colored pieces, six rods, 2 red, 2

blue and 2 white, and melted them all together for 15

minutes twisting, mixing and attempting to get a lite

purple like paint colors would make if you mixed equal

amounts of red, blue and white. As you can see from

the picture, it went muddy once more as I expected.

Another experiment:

The first picture: I spent 5 minutes twisting, blending, moving the

two colors into each other and got what could be called a green

look.  In reality, it's both the yellow over the blue and the blue over

the yellow appearing as if it changed into a new color green, but

it's (under a 20X loop) only a muddy appearing glass.  At shows
I see a few people using those magnifiers and most people would

call it a green color without those loops.

The second picture:

All I did was to lay the blue over the yellow and looked to see if they

"mixed" into a new green color. I am afraid that didn't happen with

the new glass that resembles the original Akro glass colors of blue

and yellow.

The Moretti blue isn't made with any metals nor is the yellow.

I did an experiment on both of them by raising my torch's temperature

to over 1400F and, heated the glass until it boiled - allowed it to cool,

and the glass was exactly the color it was before I boiled it proving no

metals were used in the making of the original rod.  If metals were

used, I would have melted them out and the rod would have changed



One cannot mix glass colors to make new colors

because glass colors are made from elements on the

periodic table. Glass colors can be blended.  Paint

colors can mix because the molecules will with each

other to reflect light that makes a different looking color

from the original paint’s color(s).