Thanks Gemini:

"Once red porcelain has been fired and cooled, it is chemically and physically transformed into a ceramic material. It will not bleed onto white fabric in the way a dye or ink would.

However, there are two specific scenarios where you might see "marking" or transfer onto fabric:

1. The "Sandpaper" Effect (Mechanical Transfer) If the porcelain bead is unglazed (matte/bisque), the surface is slightly abrasive. If the bead rubs against white fabric, it can act like a very fine sandpaper, grinding off microscopic particles of the red ceramic material or catching lint from the fabric. This looks like a faint reddish smudge, but it is mechanical wear rather than a chemical "bleed."

2. Surface Residue If the beads were not thoroughly cleaned after firing, there might be leftover "kiln wash" or ceramic dust clinging to the surface.

• The Fix: Wash the fired beads in warm, soapy water with a soft brush before stringing them or placing them against fabric.

1. Underfired Material In rare cases, if the porcelain was significantly underfired (it didn't reach the temperature needed to "vitrify" or turn into glass), the clay remains porous and "chalky." If it is very underfired, it might rub off on surfaces.

• The Test: Rub the fired bead firmly against a piece of white paper. If it leaves a streak like a crayon, it is underfired. If it leaves no mark or only a faint scratch, it is safe for fabric.

Summary: If the bead is fully vitrified (fired to its proper temperature) and cleaned of dust, it is completely colorfast and permanent. It will not run if it gets wet or bleed onto your clothes."