This week's poem, "My Grandmother's Opal" by Grevel Lindop, is a quest to reveal the past. The last line-and-a-quarter sums up the significance and difficulty of the quest: "this one spark / saved from the fiery heart of a lost world". Adrift in attics and cupboard drawers, such tantalising "sparks" may be all we have of that mysterious immensity, a person's life, reminding us how little we truly know the people we're closely related to: the grandparents who died before we properly "met" them; that venerable great-grandparent we just missed. Perhaps they remind us, too, of the future whose past we will sooner or later become – our grandchildren, their grandchildren. These distant relatives haunt Christmastime in our culture. To borrow the poem's words, they offer love we can never return – nor properly receive - but which can sometimes seem profoundly present.
A poet's historical imagination must work hard and tactfully in this half-world, and, while trying to salvage traces of unique reality, resist the fiction-writer's dramatisations and stay faithful to the facts and memories "sparked". Lindop's poem seems deliberately modest in form, underplaying its symmetrical quatrain structure with irregular lines and half-rhymes. The careless loss of the grandmother's photograph, regretted in the first stanza, might be the poet's blessing in disguise: the gem is a more potent object, a symbol and a cauldron. The opal's rainbow mixture evokes compression, fragmentation and buried depths.
Its colour and texture are deliciously realised in the second stanza, with the third adding to the intricacy by punningly evoking the streaks of colour as "figures". The "opulent bead" in the last line of the first stanza nicely points out the link between the gemstone's name and the idea of opulence, though there seems to be no direct etymological link. The word "opal" is from the Sanskrit, "upala", meaning stone.
The "scrying-globe" may be insufficient but it connects the poet to the vital memories from which to build his portrait. The grandmother is partly generic (there's the familiar image of the child burying his head in her skirts), yet, in the "odd scents" and the paradox of a gaze that is both "sharp" and "affectionate", the individual becomes startlingly present. You sense the depth in the woman's character here, and again, the opal's colours seem the perfect symbol of her complexity: simple sugar-white, luxurious gold and that delicate, grandmother-ish, Victorian violet.
Finally, the poem returns to the gem as physical object. It's an awkward inheritance, something that has broken away from its place in the scheme of things, and it resists modernisation or transformation: "too large for a ring, too splendid to cut down …" When the speaker describes it, in a moving phrase, as "an unexplained trust I hold", he reminds us of the responsibility to know the past, however difficult it is to decipher. The poet's particular "trust" is to use the fine, penetrative instruments of his art to further the exploration. Poetry is naturally a memorial genre. If we allow that its responsibilities extend beyond language, memory is the region where it can still recover psychological and even social usefulness without aesthetic compromise.
Finally, the poem asks the crucial question: "Where shall I set it?" This raises not only the practical questions – where shall I set it down?, how should the gem be set? – but the deeper concern about imaginative placement. And the poem itself is the answer.
• "My Grandmother's Opal" is from Selected Poems (Carcanet, 2000). Grevel Lindop's latest collection is Playing With Fire (Carcanet, 2006). His prose book about Latin America, Travels on the Dance Floor, was a BBC Book of the Week and shortlisted as Authors' Club Best Travel Book 2009. His website is grevel.co.uk. You can also enjoy the re-launched PNR website and archive at pnreview.co.uk. My Grandmother's Opal
Nowadays I can find no picture of her.
I lost the only photograph I had
moving house; nothing else came to me,
so all I keep now is this opulent bead,
milky violet, craggy sugar-white
and crumpled goldleaf fused into the one
hurtfully alluring crystal depth
of opal, her favourite stone,
which like a scrying-globe entraps the eye;
though I should need more than a jeweller's glass
to see what figures might flaw the blue mist
or walk unscathed out of that golden furnace,
distant and enigmatic, bright and small
as now my memories of her: some stories
and nonsense-rhymes she riddled me out of her childhood,
odd scents she used, her sharp, affectionate gaze,
skirts I buried my face in, and the love
which like an animal I could discern,
inhabit like warmth but never comprehend
or, so young I was, return.
So here it is, my grandmother's opal,
centrepiece of a necklace broken and strewn
who now knows where? And of no use to me,
too large for a ring, too splendid to cut down,
message I can't read, riches not mine
to spend or give, unexplained trust I hold.
I keep it: but where shall I set it, this one spark
saved from the fiery heart of a lost world?