Found new owner
The sandblast finish is considered to be invented by Dunhill, at least this fact was confirmed with patents of 1917 - in Great Britain and 1920 - in the USA. From the very beginning Algerian briar was used for blasted pipes as it was much softer and provided deeper and more attractive finish. Although in 1960-70 the company had to use Corsican briar also, and in this case another Dunhill's patent came into play - double processing (deep shell). It turned out that any material could provide the necessary result, you just need to have an appropriate technology near at hand. As an example - this wonderful diplomat shaped pipe from 1978.
The pipe markings are "51281", "DUNHILL SHELL \ MADE IN ENGLAND 18". The length is 14.8 cm (5.83"), bowl's height is 3.7 cm (1.46"). External diameter of the bowl is 4.5 cm (1.77"), internal diameter is 1.9 cm (0.75"). The depth is 2.8 cm (1.1") and this pipe weights 47 gr. Briar, vulcanite stem (slightly corrected, you may see the track under a good light), no filter. The chamber has been protected with a break-in coat. The shank had a couple of neat cracks which were carefully fixed and the shank has been clamped by a collar for the maximal reliability.