Ambergris glass, also called to as Topaz or Spanish Yellow.  It was called "oil glass" by the workers at the Vineland Flint plant.  This was probably the most common used glass by Durand for the art glass.  It was used as the base glass for most pieces and very important to the making of any Lustred glass.  Spanish Yellow was the name most used to describe tableware sets and stemware.  In the book "Durand The  Man and His Glass" written by Edward J. Meschi there are many examples of this glass shown.  Below are photos of examples from my collection.  Some have never been shown in any publication.

One of my favorites, a freeblown console set in ambergris.  A very rare set.  This is the first set of candleholders I have seen in this style.  Blown as part of a dinnerware set it is considered as Durand Commercial.  Most likely blown by Emil Larson, 1925 to 1931.  The bowl is big, 14" wide by 4" tall!  The candlesticks are 4 3/4" tall, have a 4 1/2" base and are 4 1/4" across the top.

This is a rare piece.  It is blown in ambergris glass and it is not uncommon to see tableware done in this glass but this is the first one I have seen blown using a snap ring which means it was mold blown.  The snap ring allows for the pieces final finishing inside the glory hole.  It is 11 5/8" wide, 3" high and has a 4 1/2" base.