Crystal Ball

Explore crystalline glazes to learn how they work, how they don’t work, and how they can be better.

Course Overview

Join us as we gaze together into our crystal ball and examine the mysteries of crystalline glazes…and discover there is no magic! Crystalline glazes are wonderous to observe but challenging to make, but they aren’t magic, they are chemistry. In this course, we will dive into exploring how and why crystalline glazes actually work, testing new and interesting glazes, and look into what we still can discover about these amazing glazes.

Sample Video

Course Outline

Week 1

  • TESTING GLAZES – Getting Testy
  • KEEPING CONTROL – Self Control
  • GLASS AND CRYSTALS – Pain in the Glass
  • SIDEBAR – Just a few random notes
  • BAD HABITS – The ruffling of the feathers begins…

Week 2

  • WHAT ARE CRYSTALLINE GLAZES? – What are glazes, is the better question…
  • CHEMISTRY 101 – Better living through chemistry
  • ATOMS… – Never trust
  • SIDEBAR – Material Science
  • PERIODICALLY – I have this talk…
  • MOLES – Get out your calculator
  • MOLAR EXTRACTION – This will be slightly less painful than a trip to the dentist

Week 3

  • MATERIAL BASICS – ‘Cause we’re living in a material world, and I am a materials…ceramicist
  • GEOLOGY – Rock Stars
  • SILICA – Very Sili
  • ALUMINA – Aluminia?
  • KAOLIN – Stacks on stacks
  • METALS AND EARTHS – The name of our heavy metal album

Week 4

  • FELDSPARS -Rock and Roll
  • FRITS – Puttin’ on the
  • ALKALINE EARTHS – Down to Earth
  • FLUX – Aeon?

Week 5

  • FORMULAIC – This story is totally predictable
  • SEGER – Temperature is chemistry and chemistry is temperature
  • STULL – The better way
  • STULL DETAILS – The chemistry is in the…
  • LIMITS – Sidebar

Week 6

  • THE CRYSTALLIZATION ZONE – You are about to enter another dimension. A dimension not only of sight and sound but of mind. A journey into a wondrous land of imagination. Next stop…
  • FRIT BACKGROUND – About Frit
  • CRYSTALLINE FRITS – Compare and Contrast
  • THE PHASE DIAGRAM – It is just a phase
  • WHY ARE CRYSTALS? – This is not a sentence

Week 7

  • REVIEWING RECIPES – Crystal clear
  • ALUMINA LEVELS – “Clay in your glaze will kill the crystals” – Everyone
  • ZINC LEVELS – “This glaze isn’t right, so I’m going to tweak the Zinc” – Everyone
  • TEMPERATURE – “I fire to cone X” – Everyone “No you don’t”- CMW
  • 3110 VS. 644 – Am I Boron-ing you?

Week 8

  • MAPPING – Star Maps
  • MAPPING 1270°C – Map Quest
  • MAPPING 1250°C – Map Quest 2 – The Questioning
  • MAPPING 1260°C WITH COPPER – Map Quest 3-Return of the Crystals
  • 1.5 AND 2.0 SILICA AND TEMPERATURE – Compare and contrast
  • 2.0 SI – VARIABLE AL & TEMPERATURE – The same, but different
  • SIDEBAR – Calcined kaolin did what?
  • TEMPERATURE ARRANGEMENT – The same, but different, different
  • TEMPERATURE ARRANGEMENT – The same, but different, different, different

Week 9

  • ALKALI METAL FLUXES – Don’t matter
  • TOTAL FLUX RATIOS – Various Si and Al
  • AM FLUXES AND ETCHING – Sketchy Situation
  • ION EXCHANGE – We return to our party, already in progress
  • ETCHING MAPPING – Cartography
  • ETCHING AM VS. AE – Totally Etchy
  • 1246 °C v. 1266 °C – Running hot and cold
  • ZINC – CALCIUM TRANSITION – 1.5 vs. 2.0 Silica
  • SILICA AND FLUX RATIOS – Repeat from last week
  • OTHER ALKALINE EARTH FLUXES – The other white flux

Week 10

  • TITANIUM AND ZINC – Of course, crystalline glazes have to be different…
  • PUSH IT – Push it real good
  • MATTE CRYSTALLINE – I’ve heard all the Matt(e) jokes before…
  • MAPPING MATTE – Matting Map?
  • MATTE LEVELS – Spirit level
  • COLORANTS – Color run
  • COLORANT COMBINATIONS – Thanks to Marie Wright
  • STAINS AND SLIPS – Sub-terficial
  • THE EFFECT OF COPPER – Flux reactions
  • REDUCTION – Reductionist
  • CHROME – MOLYBDENUM – TUNGSTEN – The most uninformative segment of the entire class

Week 11

  • HOW TO LOWER TEMPERATURE – How low can you go?
  • LITHIUM CARBONATE – What Lithium Carb is and what it isn’t
  • BORON – The get down
  • BORON LEVELS – Boron Again
  • CONE 6 FLUX RATIO – The fightin’ 6th!
  • CONE 6 CRYSTALLINE MAPPING – 0.22:0.78 (0.55 ZnO:0.23 CaO) – 0.12 Boron
  • ANTI-BORON – Remember how I’ve said not to use pure Alumina?
  • BRISTOL GLAZES – I Bristol at your suggestion…
  • BALANCING BRISTOL GLAZES – Balance to the force…
  • LEAH LEITSON CHUN – Breaking Good
  • BRISTOL & TOTAL FLUX RATIOS – Things get weird
  • ETCH-A-TEST – That etch you want to scratch

Week 12

  • APPLICATION – Apply yourself
  • GRAM WEIGHT IN ACTION – TC Staton in action
  • BISQUE – Biscuit
  • CLAY BODIES – The cornerstone of glaze application
  • WATER AND VISCOSITY – Water, water everywhere
  • CRYSTALLINE EFFECTS – Wreckx-n-Effect
  • NON-ZINC CRYSTALS – Everything but the kitchen Zinc
  • EXPERIMENTS TO TRY – Blast off!
  • IN CONCLUSION – In conclusion

Course Announcements

Now enrolling in October 2024 Session

  • ​Class size is limited and typically fills before start date of Oct 1st
  • Sign up today to reserve your spot!

Coming Soon!  Self-Guided Crystal Ball

  • Adding to our self-guided course options this summer!


Lectures Only Vs. Full Course

Lectures Only Option – $500

You can begin right now.

Enroll and start learning today!

 If you want just the lectures:

  • You can start RIGHT NOW!
  • $500 for unlimited access to all of the Crystal Ball lectures
  • Over 22 hours of content
  • Includes four months of access to course materials
  • Upgrade option available to full course for only additional tuition + upgrade fee $50
  • Enroll Here!
  • Note this option does not include labs or live Q&A discussions

If you want more, we’ve bundled together our favorites for you!

 Our new Premium Add On includes:

  • Lifetime access to all 3 CMW Workshops – Glaze Our Lives, The Middle Glazes and Glazed & Confused!  ($300 value)
  • Lifetime access to the new CMW Digital Glaze Book with Matt’s Analysis ($250 value)
  • Can be added to any Lectures Only, Self-Guided or Full Course
  • Save $250 – A $550 value!
  • Cost:  $300

Full Course Option – $700

Now Accepting Enrollment in October 2024 Session!

Class size is limited!

 If you want to experience the full course:

  • The next class session begins October 1st with 4 months of access
  • $700 for the full experience
  • Full experience course includes:
    • 12 weeks of on-demand lectures with over 22 hours of content
    • Live bi-weekly online Q&A discussions with Matt on Wednesdays 8pm and Thursdays 10am EST (NYC time)
    • Optional lab experiments and readings
    • Access to Course Discussion pages to ask questions about class content
    • Copies of lectures materials
  • Registration is now open and is LIMITED!  Reserve your spot now!
  • Sign Up HERE!
  • We’ve bundled together our Lectures Only courses at a great price of $1,400!  Save $300!

    • 16 months of unlimited access to Lectures Only Understanding Glazes, Lectures Only Intro to Clay Bodies, Lectures Only Advancing Glazes and Lectures Only Crystal Ball.
    • Upgrade option available to each of the full courses for only additional tuition + upgrade fee $50 per course
    • Enroll Here!
    • Note this option does not include labs or live Q&A discussions


Meet Your Instructor Matt Katz

Matthew Katz

Matt Katz has been teaching for years at world class institutions including The New York State College of Ceramics at Alfred University, Rhode Island School of Design and Harvard University.

Course Reviews

What Students are Saying


“One can always want more – it’s the nature of good learning – but this class has been a great experience in every aspect. I have truly gotten both new and more in depth knowledge. You’re a great teacher and you’ve built a really good and respectful, non-prestigious learning environment around your classes. No question is too little or too big.”


Asa L., Crystal Ball Student


This was awesome! I really feel as though all the information I learned in understanding, advancing and clay bodies were all integrated into the crystalline course. I may be the worst student you have had in terms of my actual testing, unfortunately, my day job gets in the way of my art, but once I get organized in the studio, I plan to test many of the concepts you covered. Thank you Matt and Rose for all of your hard work putting this all together into a cohesive framework. The course helped me to understand why crystalline glazes work and helped me figure out why things don’t work rather than just a bunch of recipes which are easy platitudes and provide no building blocks for what could come next. Thank you for chemistry with context!


Damian D., Crystal Ball Student


“The course seemed very thorough. I didn’t have time to finish all the labs on time but I hope to continue with the Patreon subscription. So many things to try!”


David S., Crystal Ball Student


“…it’s a fab class and has given me all the tools I need to be able to go ahead and feel confident developing my own crystalline glazes.


Kate L., April 2023 Crystal Ball Student

Frequently Asked Questions

Answers to Your Most Pressing Questions

What experience level is this class for?

Our classes are designed for makers of all levels. We’ve had professionals with 50 years of experience and we’ve had folks take our classes after having one studio class at their local community college. Everyone comes out truly understanding glazes.

Why should I take this class?

I’ve got books. Books are great, but books are a supplement and a reference in education. The reason why school is still lecture classes, is because audio/visual learning is still the most powerful educational tool.

When I first started studying glazes I got a book, and I read every word…and I understood about 1% of it. The experience of listening and looking helps us to truly UNDERSTAND a subject.

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