Could it be one of a pair of vintage cufflinks? They were probably expensive based on the intricate clasping mechanism and craftsmanship. That sunrise/sunset/sunny face may be your hallmark, but I could not find anything about it. Very cool, none the less. Sub
Originally I thought that, but there is no way you could operate this with one hand and do your cuffs.
I “think” maybe the top button of a tunic
Once again I have No clue
I'm going to guess a cufflink as well. It appears to have a name engraved on it "W Werk"? That may be a good place to start. As far as it being too complicated to operate with one hand, keep in mind that most gentlemen of means had a butler or man servant to take care of such details for them.
I don't know if this is the right path to search but the combination of the rising sun and the fouled anchor is used on Peninsular & Oriental (P&O) Shipping Line buttons and other items associated with that company.
The only additional info I can contribute is that is definitely not Military. No actual Navy emblems have that swirly background around the anchor. It is a civilian-usage "Nautical Motif" cufflink, worn by yacht-owners and other civilians who are into sailing/boating.
Be it known that I, WILLIAM WEST, a subject of the Queen of Great Britain, residing at Aston, in the county of Warwick, England, have invented certain new and useful improvements in solitaires, buttons, and analogous appliances for fastening articles of wearing-apparel, purses, bags, and other articles, of which the following is a specification. This invention relates to solitaires, buttons, and analogous appliances for fastening articles of wearing-apparel, purses, bags, and other articles; and the said invention consists in the improvements in construction of such appliances illustrated in the accompanying drawings and hereinafter described with reference thereto.