Reliquary for A Castaway

Supposed to Be Written by Alexander Selkirk, During His Solitary abode in the Island of Juan Fernandez:

I am monarch of all I survey,
My right there is none to dispute,
From the centre all round to the sea,
I am lord of the fowl and the brute.
Oh solitude! where are the charms
That sages have seen in thy face?
Better dwell in the midst of alarms,
Than reign in this horrible place.

William Cowper, 1854

A reliquary for the castaway, made of a sea bean (entada giga), hollowed and filled wiith curiosities and a scrap of antique text (said curiosities are: a bit of egg shell, a bit of nacre from a seashell, skull of tiny mammal from an owl's cast; glass beads, kanji script, a scrap of skeletonized leaf), held fast on waxed died cotton twine, suspending also a mysterious nut that looks like a chicken heart that I can't find anywhere on the net (it originally came on a string of tulsi, most likely from India). For more on the use of natural seeds, beans and such, visit the lovely collection of Ruth J. Smith, online.  You won't find the mystery nut there, however, but if you know what it is, please, please oh please, leave me a comment, otherwise I'll be thinking there's a chicken heart tree out there in India somewhere.