Tourmaline
PC-27
Tourmaline is a satin brush-on glaze from Amaco's Potter's Choice line, fired cone 5 to cone 6. Saturated, strong, gemstone.
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Friendly studio tip for this glaze
Even coats matter here. There is no break and no float to cover a thin patch, so whatever your brush does is what the kiln shows.
The quick version of Tourmaline
What this glaze does
An intense opaque blue-green with a smooth, strong surface. Where most of this line is built to break, pool and float, this one holds a single saturated color and holds it well.
The name fits: tourmaline is a stone that comes in deep blue-greens, and the glaze has that same density of color.
How much it varies
Very consistent. One of the dependable colors in the line.
Clays that suit Tourmaline
Opaque with a strong even surface. The clay body underneath has no meaningful effect, which is part of why it is so consistent.
Thirty three of these forty six glazes are opaque, so on most of them the clay underneath is a surface to sit on rather than part of the finished color. The other thirteen see through to some degree, and those are the ones where your clay choice really shows.
Applying this glaze to your work
Three coats, evenly. A saturated opaque glaze rewards consistency, since any thin patch shows as a weaker color.
How much it moves
Stable, with a strong even surface.
Amaco's instruction for the line is three brush coats, not thinned, each one dry before the next. Their own guidance says most disappointing results come from glaze applied on the light side. Amaco publishes an application guide showing what too thin and too thick actually look like.
Layering
Amaco says it goes well layered with other Potter's Choice glazes. As a solid saturated base it takes a float or a fluid top coat well.
Amaco's own combination tiles usually show two coats of each glaze, which lands four coats total anywhere the two overlap. Their standing advice is to test a tile before committing a piece, and to re-test when a new batch number arrives, since raw materials shift between production runs. Dipping versions of these glazes behave differently from the brushing jars and are much harder to layer.
From The Clay Hole University
More info about Tourmaline below, but first... Everything we teach about glazing, written down and taught properly. These are the glaze lessons, and they are a small corner of a library that runs from centering your first pot to selling your work.
GuideGlaze Brushing Techniques, Coat by Coat
GuideGlazing Big and Intricate Pottery Faster
GuideGetting the Most Out of the Mega Glaze Tool
GuideMaking, Logging and Dialing in Test Tiles
GuideGlaze Problems, Causes and Fixes
GuideGlazing on the Wheel for Even Coats and Clean Bands
GuideBubble Glaze with Dish Soap
GuideMixing Your Own Glazes: What It Actually Involves
GuideMaking a Glaze Catcher
GuideGetting Great Results with Crystalline Glazes
GuideOxide and Carbonate Washes
GuideWhen to Use Celadon Glazes
GuideHow to Use Dipping Glazes
RakuRaku Firing: Techniques, Tips and How It Works
UnderglazeHow to Use Underglaze: Techniques, Rules and Firing
UnderglazeMishima: How to Inlay Slip and Underglaze into Carved Lines
UnderglazeWipe-Away Texture: Underglaze and Oxide Washes on Bisque
Firing Tourmaline
Amaco rates the line for cone 5 and cone 6, published as 2167F and 2232F on a medium speed firing, over bisque fired to cone 04.
None of this is yours to manage. We handle everything on the kiln side, and every glaze on our shelves can be fired safely in our studio.
Common problems with Tourmaline
Why is my color patchy?
Uneven coats. This glaze has nowhere to hide a thin spot, since it does not break or float.
Why is there no variation on my texture?
It is not designed to break. Choose a breaking glaze if you want the relief to draw itself.
What to put it on
Forms and surfaces
Forms with good profiles that do not need surface help. Also a strong base under a fluid or floating top coat.
Colors beside it
A saturated blue-green stands on its own. Cream, bare clay and warm browns all frame it well.
Food and function
Amaco rates this glaze food safe and dinnerware safe, lead free and AP Non-Toxic. Its evenness makes it a practical choice for matching sets.
Every glaze in the line is lead free and, by Amaco's rating, dinnerware safe except PC-4 Palladium and PC-64 Aventurine. Amaco's own label carries the standard caution that anyone producing tableware should test finished ware, because firing temperature and contamination vary between kilns.
Our test tile pots
Every glaze family on our shelves has its own test tile pot, and it is the fastest way to decide what to put on a piece. It is a fired pot wearing the whole family, one numbered tile per glaze, on a surface built to show you what that glaze actually does rather than just what color it is.
- 1Find the pot The brand and family name are written on the rim. This glaze lives on the Amaco Potter's Choice pot.
- 2Find the tile This one is tile #14. The numbers match the ones in the Glaze Bible.
- 3Read it properly Look at what the glaze does across all four textures, not just what color it is.
What to look at on the tile
Some glazes tell you loudly that they run. Others hide it. Look at how the brushed lines fired: crisp edges mean a stable glaze, and edges that went soft and fluid mean it moved, and it will move on your pot too.
Other glazes close to Tourmaline
Lustrous Jade is the green version of the same idea. Satin Oribe covers the blue-green ground in a matte. Blue Stone softens it into a muted matte.
Looks great paired with
Put these on the shelf beside it, or on the next pot in the same set.
About the Amaco Potter's Choice Family
Potter's Choice is the line Amaco built so an electric kiln could do what a gas kiln does. Released in 2004, it reaches for the depth of cone 10 reduction glazes at cone 5 and cone 6 in ordinary oxidation. That is the whole premise, and it is why the surfaces break, pool, float and shift instead of sitting flat.
It is one of the most layered brushing lines in American pottery, and Amaco keeps a public library of combination tiles for it. Most of the effects potters chase come from two of these glazes meeting on one pot.
Made by Amaco, a company that has been building glazes and kilns in Indianapolis since 1919. The Potter's Choice line arrived in 2004 and has been a reference point for mid-fire reduction looks since.
More ways to pick a glaze
Membership levels that may use this glaze: Purple & Black
Not sure whether this glaze suits what you are making, or how it works with our system here? Ask an instructor. That is what we are here for, and a two minute conversation at the shelf beats a fired pot you did not want.
About these images and what your pot will actually look like
We have done our best to represent every glaze here accurately, and you should still expect your pot to look different from what is on this screen.
Our glaze tile images are digitally created. They are built to show the character of a glaze, not to be a color match.
A screen is not a printout, a printout is not a test tile, and a test tile is not a finished pot. Each step in that chain shifts what a glaze looks like, sometimes a lot.
On top of that, the pottery itself changes the result: the clay body, how thick the glaze went on, whether it was brushed, dipped or sprayed, what was layered under or over it, where the piece sat in the kiln, how hot that spot ran, how fast it cooled, what was fired next to it, and how much texture the surface had. Two pots glazed from the same jar on the same day can come out different.
Treat every image here as a starting point, and treat a test tile fired on your own clay as the real answer.