Bob Bjork responds on Marshall Ketchum’s piece on the whites
I would like to commend Marshall on doing an excellent job of explaining the Steuben whites. I would like to add that it has been my experience that Ivrene, when signed, is more commonly signed by diamond point in script.

Also, when used in conjunction with acid cut back, Ivory is sometimes signed with the large fleur de lis within the ACB design. Also some ACB’s with an alabaster body (such as the pussywillow) are also signed this way.
Next, some additional information from David Goldstein.
Marshall’s explanation is both accurate and complete. However, I would like to add a couple of comments. First, there is no such glass as Ivorene, which is a common corruption that is often seen where someone does not understand the difference between Ivory, which is a light yellow custard color, and Ivrene, which is a.bright, iridized white. Second, thick pieces of Flint White such as perfume stoppers may seem to be opaque even though the glass is actually translucent.