Something wonderfully round and opalescent about these glowing pearls likened to the pearly eggs of a ‘vast moon-spider’.
‘… so that her pearls glowed like the eggs of some vast moon-spider.’
For another pearly metaphor, see this in Nikos Kazantzakis’ The Last Temptation.
Source: Virginia Woolf, Orlando: A Biography, ed. with an introduction by Rachel Bowlby (Oxford: World’s Classics, 1992), p. 313