Can a tag be embedded in wood, leather or ceramic?
Electrically yes, since none of them is conductive and the field passes. What differs is the process and how the material moves afterwards. Ceramic and glass are formed far above anything a tag survives, so the tag arrives after firing, and wood and leather keep moving while the inlay inside them does not.
The field is not the problem
Wood, leather, ceramic, glass, stone and concrete are not conductive, so they do not cancel the field the way metal does. The materials page says it plainly, and the wooden card page says the objections to wood are mechanical rather than electrical.
Two caveats attach to that. Water attenuates, which the water page covers, and green timber, damp leather and fresh concrete are all wetter than the object they become. Test the material in the state it will be in.
And decoration is often metal. Gold lustre on porcelain, metal leaf on wood, foil stamping on leather: a metallic finish over the antenna puts the piece back in the metal case, whatever the body is made of.
Wood and leather keep moving
Wood takes up and gives off moisture with the air around it and changes dimension as it does. The inlay inside does not, and over time that difference works at the bond between chip and antenna, which is the weak point of any tag.
Leather does the same for different reasons. It is worked wet, it stretches where it is handled, and it is thinned, stitched and finished with chemistry the tag has to sit next to.
Neither is an argument against embedding. It is an argument for a sealed tag body rather than a bare inlay, for a recess that holds the tag without clamping it, and for a sample that spends a month in the real environment before a production order.
Ceramic and glass are fired first
Firing and glass forming happen far above anything a tag survives. There is no tag to be glazed in, and the question answers itself in one direction: the piece is made, then the tag goes into it.
The usual route is a recess in the foot or the base, with the tag set in and closed with a felt pad, a cork disc or a potting compound. It also solves the tap point, because the base is where a hand can present the piece to a phone.
Ceramic bodied tags exist and are a different product. They are built for processes that pass a tag through an oven, as the temperature page describes, and they do not turn a kiln into something a tag can survive.
Getting the tag in
A routed or moulded recess, closed with a plug or a pad, is the route that works in every one of these materials and asks the least of the tag.
Pressing a tag between plies, in veneered or laminated wood, is heat and pressure together, the combination the moulding page treats as a process to qualify rather than a step to assume.
Encode after assembly where the material allows, since all of these pass the field, and read every finished piece back. On a made object the loss is the object, not the tag, which is the argument for verifying before any finish goes on.
And mark the spot. On a handmade piece the mark is a design decision rather than a label, and the marks page covers what the NFC Forum licenses for it.
Frequently asked questions
Can a tag be fired into ceramic?
No. Firing is far above what any tag survives. The recess is formed in the piece and the tag goes in after the kiln.
Does wood block the field?
No. Wood is not conductive. Thickness and moisture cost a little range, and a metallic finish is a separate problem.
Will a tag survive being pressed into plywood?
That is heat and pressure together, the combination that breaks chip bonds. It is a process to qualify on the real press, not to assume.
What about dyed or waxed leather?
The chemistry is a question for the tag body rather than the chip, and a sealed construction handles it better than a bare inlay. Test on the real process.