| 501 / | HD | COMPOSITIONS: CERAMIC |
| 1 | DF | CERAMIC COMPOSITIONS {15} |
| 11 | DF | .~ Glass compositions, compositions containing glass other than those wherein glass is a bonding agent, or glass batch forming compositions {11} |
| 41 | DF | .~.~ Nonsilicate oxide glasses {4} |
| 49 | | .~.~.~ Boron containing {2} |
| 50 | DF | .~.~.~.~> And yttrium or rare earth (i.e., elements with atomic numbers 39, 57-71, or 89+) {1} |
| 52 | DF | .~.~.~.~> And aluminum or beryllium |