German, Hoyermann Phosphate Factory, Hannover, Seal

Star of David, PH, Seal, Image by StuE, Found by Garry J.
Found in Yorkshire, 20mm.

This seal needs to be examined in conjunction with the other 5 found by Garry J. They are obviously the same type of seal and together a near complete description can be compiled though it is sadly uncertain in vital areas so far.
Three show the Star of David with a PH ligature at its centre. Two indicate that HANOVER is written across the middle and all contribute to the writing curved around the outer edge:-
S.PHOSPHATE(A?)(B?)(R?)IK(H?)(D?)(Y?)ERMA(---?)

From Paul Cannon:- "From the following I can suggest the probable unreadable letters on these seals. They most likely read around the circumference: PHOSPHATFABRIK HOYERMANN and across the centre HANNOVER ie Hoyermann Phosphate Factory, Hannover. The following is a link to a paper seal of the same company which incorporates the same PH monogram within a six pointed star Phosphatfabrik Hoyermann - Hannover.
They are all definitely chemical fertiliser seals. For a description of the founder of the firm Gerhard Hoyermann see Gerhard Hoyermann, Wikipedia. The following is an extract: “he developed from phosphorus slag a blast furnace plant fertiliser ‘basic slag’ for agriculture. In 1881 he founded the Peine phosphate factory, which was followed by other factories in Germany, Bohemia and England.’"