• Casein: fish scale pearlized, England, sew-through

    This button is a press-molded wafer. Back marks are uncommon in casein buttons.

    Casein identification guide: casein is a thermoset semi-synthetic polymer made from milk, hardened in formaldehyde

    7. Many pearlized caseins, made by mixing fish scales into the plastic batch.

    source: Button Materials A-Z: Identification Guide
    by Jocelyn Howells

    Button Specs