Ancient Jasper
PC-53
Ancient Jasper is a satin brush-on glaze from Amaco's Potter's Choice line, fired cone 5 to cone 6. Earthy, geological, active.
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Friendly studio tip for this glaze
Three colors live in this jar and thickness is the dial. If you want the reds, load the brush and keep going past the point where you think you are done.
The quick version of Ancient Jasper
What this glaze does
Three colors in one jar, and which one you get is decided entirely by thickness. Thin, it fires a soft black. A little heavier, olive green. Heavier still, rust red. On one pot with any relief at all, you get all three at once.
The reds come through on any clay, but iron-bearing bodies pull a wider spread of color out of it. It has an active surface on its own before any layering enters the picture.
How much it varies
Highly variable by design, and Amaco says so. Thickness, clay body and firing all shift the balance between black, olive and red. Test a tile on the clay you actually use.
Clays that suit Ancient Jasper
Amaco is specific here: the reds come through on every clay body, but an iron-bearing clay pulls a wider spread of color out of it. If you have a choice of clays, that is the one to use for this glaze.
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
Amaco says outright that this one benefits from a heavier application, and the reds are the reward. Three full coats minimum. Thin coats give you the black end of the range and none of the drama.
How much it moves
A fluid glaze. It will travel down a vertical wall, which is part of how the three colors separate. Give it room at the foot.
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 calls the results striking when layered with other Potter's Choice glazes, and its own varied surface means it brings something to any pairing rather than just sitting underneath.
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 Ancient Jasper 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 Ancient Jasper
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. One specific instruction from Amaco: no special cooling cycle or soak is needed, and a soak can actually take the reds away. If your kiln holds at temperature, that is working against this glaze.
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 Ancient Jasper
Why is mine black with no red in it?
Too thin, or the firing soaked. Thin coats stop at the black end of the range, and Amaco warns that soaking diminishes the reds.
Why do my two pots look completely different?
Because thickness controls the color and iron in the clay widens the range. A different clay body or a heavier hand changes the result substantially.
Why did it run?
It is fluid by design, and a heavy application makes it more so. That is the trade for the reds.
What to put it on
Forms and surfaces
Carved and textured work, where the three colors can separate across a single surface. Strong on iron-bearing clays. A good choice when you want one glaze to do the work of a whole palette.
Colors beside it
Rust, olive and black together read as earth, so it belongs beside browns, tans and deep greens. A cool blue nearby makes the red end look hotter.
Food and function
Amaco rates this glaze food safe and dinnerware safe, lead free and AP Non-Toxic. Worth remembering that a heavier application is what produces the reds, and heavy applications on functional ware still need clearance at the foot.
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 #5. 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 Ancient Jasper
Ancient Copper shares the weathered iron story with more copper in it. Deep Sienna Speckle is the calmer russet. Temmoku holds the dark brown end without the color shifts.
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.