Sussexite is a very uncommon mineral. While it is know from more than a dozen localities, only a few have produced specimens with Mindat photos, and large specimens, such as this one, are only available from the Franklin and Sterling Hill ore bodies. (The co-type localities are all various openings in the Franklin ore body. The Sterling Mine, which this is from, is not one of the co-TLs.)

At Franklin and Sterling Hill, sussexite has two very different habits, fibrous (generally white unless stained) and cherty (generally pinkish to purple). It can be hard to believe that these two manifestations are the same mineral. This specimen features the fibrous variety. 

In addition to a couple of full-view photos, I have provided a micro close-up (FOV 6.9 x 4.4 mm) of a small sample of the sussexite fibers. The matrix is lean franklinite/willemite ore in very weakly fluorescing calcite.

This is a “near-museum-size” specimen. Unfortunately that means that postage for non-USA buyers will also be “near-museum size”. For USA buyers, things are not so bad. I will use a medium USPS Priority Box. You could even stuff in additional items for the same rate.