'I know I should be most impressed by the size of it, the cut, that it's perfect and flawless,' Kitty said, 'but what gets me is the colour. I've never seen colour like it.'

'Colours,' Eric quantified and for once Kitty didn't chip back at him.

'Trichroic I love that word,' Gina said, holding out her own hand onto which Petra carefully placed the stone.

'Part of tanzanite's great allure is that it is trichroic,' said Petra, 'that it actually radiates a different colour from each of its axes. It's not a trick of the light. Those different colours exist, simultaneously. Look through it this way how vivid is this blue? Now look that way-'

'As dreamy-violet as Elizabeth Taylor's eyes.'

'G.o.d, you're so gay, Eric.'

'Sod off, Kitty. It's as if a violet-blue flame burns at the heart of the stone.'

Gina had gone very quiet, mesmerized by the tanzanite nestling on her fingers. 'And you won't sell it? You really won't sell it?'

Petra shook her head.

'Thought not and still no clearer what to do with it?' Petra gazed at the stone. 'I have ideas but I don't know yet what this stone wants to be.'

'It would make one huge f.u.c.k-off ring,' Kitty laughed.

'Isn't tanzanite too soft for rings?' Eric asked.

'That's a bit of a myth really,' Petra said. 'I mean, tanzanite is nowhere near as hard as diamonds but it's still a 67 on the Mohs scale so it's hardly soft.'

'Shaun Leane produced some stunning rings with tanzanite.'

'But I don't know if my tanzanite wants to be a ring. I feel it should be seen in the round. Somehow.'

Gina pa.s.sed the stone to Kitty who smiled and smiled, a warm gentleness washing over her face as she gazed into the depths of the stone. 'It seems to go on forever,' she said.

'I think it was of its time to leave the pavilion at the base open, not finish it to a precise ridge or point possibly because they didn't have the cutting technology in the 1960s that they have nowadays. But in all other respects, the proportions of the cut are near perfect.'

Kitty admired the flat table at the topmost part of the stone, then the crown facets, the girdle, the pavilion.

'My go,' said Eric, who held it up to the natural light, moving it between finger and thumb so that colour and light and energy shot out. He draped the velvet pouch over an upturned plastic cup and balanced the tanzanite on top. 'If that's not the ultimate touchstone of inspiration for us all today, then what is!'

And they set to work. Every now and then looking up intentionally or otherwise to catch sight of the rare profound blueness, the flashes of violet, the sparkle and the beauty. The gem seemed to hum, to have a resonance that flowed into the room and touched the tools, charging the jewellers' hands as they worked.

'The thing is, even when you've made it up into something will you actually be able to sell it then?'

'It depends if I win the lottery in the meantime,' said Petra.

Mid-afternoon, Petra announced that she was sloping off. 'And the tanzanite is coming with me.'

'Spoilsport,' pouted Eric.

'Don't stick your tongue out at Petra,' Kitty barked.

'I'm taking it straight back to my bedroom. Then I'm going to nip round to Rob's flat before I meet him in town this evening. You know scatter rose petals, put champagne on ice, a silk blindfold on fresh sheets.' Though she said it lightly, Petra's Studio Three could see how earnest she was.

'He doesn't deserve you,' Gina said, so kindly that Petra heard it only as a compliment. And though Kitty made vomiting gestures, she did so with a soft wink.

'Well, have a lovely time,' Eric smiled but with a sly barb to his voice. 'You can thrill us with the details when we see you on Monday morning.'

Petals. Can one actually buy petals or must I demolish entire flower heads? Do roses have a season? How far will the petals from a dozen roses stretch? Perhaps I ought to buy two dozen. And will they still be fresh and fragrant by late tonight or might they wilt and discolour? How can I prevent that? Perhaps I should ask the florist for the tricks of the trade. A florist or a wedding specialist. Or a romantic novelist. Oh shut up, me.

Champagne. I don't really know much about champagne because I don't really like it. But Rob does. Isn't Bollinger a bit cliched? Bolly this, bolly that? I could buy pink champagne to colour-coordinate with the rose petals but Rob probably won't notice that. And perhaps pink champagne is naff. Look at the choice, even here in my local offy. I can't p.r.o.nounce that one but fortunately I can reach it. It's pretty expensive so it must be good.

I'll take my Diptyque candle and some matches and I'll light it as soon as we're through the front door. Chocolates! Hand-made truffles! There's that shop in Islington it's walking distance from Rob's. I'll go there on my way to his.

What else what else what else.

Does Rob have a bucket?

Music! I can't work his iPod so I'd better set up a CD and then all I'll have to do is press Play when we get back later.

Play indeed. This is fun! I hope he'll love it. I hope it touches him. I hope he'll really love me for it.

But maybe this is all a bit over the top. Perhaps it'll irritate him. Perhaps it's not his thing at all, though it's very me. Maybe I should just go and meet him in Soho as arranged and not bother with all of this.

But just before six o'clock Petra arrives at Rob's flat, laden with all the things she can think of, all the things she can just about afford, and a couple of things she can't really afford, to make his birthday unforgettable. To ensure his birthday goes with a bang. To guarantee this will be a memorable day in their relationship. She's proud of herself and excited. And she's just let herself into Rob's flat.

Something is wrong. Instinctively, Petra knows that something is very wrong. She surveys the scene fast. Everything looks almost as it should. But only almost. Because there are two pairs of shoes that have been kicked off near the sofa and only one set belongs to Rob. And Petra allows herself just a moment to think that it would be fine, it really truly would be fine, if perhaps those spike heels were actually his too and simply exposed a secret cross-dressing proclivity. That it would be all right. Funny, even.

However, in those heightened milliseconds of being able to circ.u.mnavigate the entire scene of her imminent destruction, Petra knows that her straw-clutchingly pathetic notion is far from the truth. Somewhere in Rob's flat is the naked truth possibly the b.u.t.t-naked truth but Petra doesn't want to go looking. She sits down on Rob's sofa and does not look at the shoes. She concentrates on holding tight to the flowers and the chocolates and the champagne and the tin-foil which she was going to wrap around the bucket to cool the champagne. She's holding on as tight as she can while she sits there waiting to be found.

Rob saunters through, whistling, and stops abruptly and says, f.u.c.king h.e.l.l, Petra, what are you doing here? And Petra stands up and says, I was going to give you the best birthday ever. And then Laura walks in Rob's workmate, the nice one, the one who was kind to Petra that night in town quite recently. And the thing is, it's not as if they're naked. So maybe they were in Rob's bedroom because Laura wanted to see, just wanted to see his built-in wardrobe. Or his ensuite walk-in shower. Something like that. Because Petra heard the shower going. Because perhaps Laura has just bought a flat. Or something. Innocent as you like. Because they have their clothes on. And it's six o'clock on a Friday. And Rob is meeting Petra in town, for his birthday, in an hour's time. But all this reasonable blamelessness lasts just a split second.

Their hair is damp. And, at the very moment that Petra clocks Laura's bare feet, Laura says, Oh G.o.d, Petra! Oh s.h.i.t! It's not what it seems! It's just you know! And in a glance Petra can see that Rob's expression is telling Laura to shut up, shut the f.u.c.k up.

'Rob?'

'Petra I can explain.'

'Go on then.'

But he can't very well explain with Laura there so Laura says, Oops! I'd better go. And once she's gone, Rob looks at his girlfriend of ten months and he shrugs.

'I didn't mean to hurt you, Petra,' he says. 'Honestly. It's nothing serious.'

'Nothing serious? The thing is, Rob, I don't know if you're referring to me or her.'

'Her!' Rob says too quickly. 'We just got p.i.s.sed at lunch-time you know what it's like.'

But Petra doesn't because Rob inhabits a world so different from hers.

'It was stupid. It didn't mean anything. It doesn't matter.'

But it matters very much to Petra. It means everything to her. And she feels very very stupid. And rather sick. She drops all the things she's been holding onto so tightly, all the accoutrements for a stupid b.l.o.o.d.y happy sodding birthday. And she bolts from Rob's flat and out into the lively thrum of Upper Street, Islington, which is buzzing on a Friday evening as people start to celebrate the end of the working week and all the fun of the weekend ahead of them.

Chapter Twelve.

What is she going to do?

What can she do with this information?

What is she going to do with her night, with her weekend, with her life, with her tomorrow?

Who can she turn to right now? No one should have to weather a trauma like this alone.

Petra Flint may be a romantic but she's also fairly sensible. She would quite like to throw up in the middle of Islington but she breathes slowly and methodically instead, to calm herself and quell the nausea. She could easily collapse into sobs at the bus stop but she bites down on her lip and decides to hail a taxi. What price the security of home?

And quickly, please. I know it's rush-hour but if you could drive like the clappers I'd be grateful.

Train to catch, love?

No. I just want to be home.

Well, it'll be sticky up the Archway, love, but it'll ease out after that.

Sticky up the Archway. Sticky up the arch way. Stick it up yer archway. To Petra, just then, it sounds bizarrely vaudevillian and she is taunted by an image of a sticky sweaty Rob pushing up into Laura.

Petra is home.

The solitude and safety of her own s.p.a.ce render obsolete the composure she maintained so brilliantly in Islington and in the taxi. She closes her front door and presses her back hard against it. Then she doubles over, clutching her stomach. She drops to her knees and cries, No no no, hammering her knuckles against the carpet. She curls herself onto the floor just inside the door even though she's within arm's reach of the sofa. She can't cry properly and it is painful. The sobs are caught like sharp obstructions in her throat and she can no more swallow them down than she can wail them up. Her tears try to itch and ooze their way past aching eyeb.a.l.l.s as if her tear-ducts are constipated. She is light-headed but the pit of her stomach is leaden. Her brain is having difficulty computing all the immutable information and her heart hurts. It simply hurts. From a situation so sordid, comes pain so pure. It's all unfathomable.

She woke up pleased to find herself still on the floor near the door, because such a trauma could well have had her sleepwalking way past Whetstone. Common sense told her not to mope and not to be alone and the hands of her watch said that, at just turned tomorrow, it would be breakfast-time again in Hong Kong.

'Luce?'

'Stay right there I'll phone you straight back.'

The beauty of your oldest, closest friend is that, in a crisis, she has no compulsion to do anything other than come to your rescue. She puts her life on hold as she steps into your shoes to fight your corner for you. Because she can feel your pain, so she can take just a little bit of it away. She won't mince her words or indulge you, she'll talk to you straight and tell it how it is. But she'll also intersperse her constructive help to there-there you like a mother. In Petra's case, in lieu of her mother. And she'll carefully lay the foundations of her advice on a soft bed of much-needed sympathy.

So Lucy listened and gasped and squeezed her handset tight as if it was Petra's hand or Rob's sodding neck. She was livid and distressed and frustrated by the distance that separated them. She was outraged and felt Petra's pain as keenly as if it was her own. After Lucy had done listening because Petra was done talking, she soothed her with utter sympathy and a genuine croak to her own voice. Encouraging Petra to use the phone call to sob all she wanted, Lucy willed her affection and her support to traverse the Pacific or bounce off the telecommunication satellite or whichever route was the quickest to go down the phone and into Petra's soul. And only then did Lucy take charge of the situation and of her friend's immediate future.

'This will not damage you, Petra, because the problem is his and not yours. It's your opportunity to wrest your life back from the hold he had over you. You are allowed to hate him. You can enjoy it. Then you might well pity him. And soon enough I promise you you simply won't think of him at all. If you find yourself missing him, ask yourself what it is you miss.'

'But I worked so hard at loving him.'

'You worked too hard at loving him for too little return.'

'But he didn't love me.'

'You are right but that's his shortcoming, not your failure.'

'I tried so hard.'

'It is not your fault. He probably does love you in his own half-baked way. Love means different things to different people. It's the centre of your world but it's on the periphery of his. But he'll probably make a play to get you back.'

'Do you really think so?'

'You shouldn't be sounding hopeful you should be sounding horrified. You are better off in the long run. Please believe me. If he comes crawling and begging and dripping with diamonds please say no.'

'It's all right for you, Luce. You're married and sorted. I'm on my own.'

'Better to be on your own than settling for so little. You shouldn't be with Rob to make yourself feel better, because I'm telling you, Rob did not love you as you should be loved. And he won't miraculously change. You know what I think, Petra, I think deep down you were never sure about his feelings for you and that's why you tried so hard. G.o.d, it was like a full-time job the effort you bestowed. You worked so hard at being a s.e.xpot, a wifey, a fascinating person, an amazing girlfriend.'

'What more could I have done? Why wasn't that enough?'

'You are trying to measure yourself against how much affection you could inspire in him. That's why you're feeling so wretched because you are judging yourself on how little he loved you. All you expected in return was respect, affection and fidelity none of which he gave you. But you listen up, Petra he didn't not love you because you're unlovable, my darling. He's emotionally imbecilic. You must not take this personally.'

'How can I not?'

'I know. I know. At this stage, that's impossible. Answer me this, though. If he came round right now and asked you to marry him, would you say yes?'

'Yes! I would! I would say yes yes yes!'

'Petra, if he came round right now and asked you to marry him tomorrow, would you say yes?'

The line went silent. 'Petra?'

'I ...'

'Would you? Would you marry Rob tomorrow? I'll come over I'll go to the airport right now. Will you marry him tomorrow? Marry him tomorrow and forever?'

Silence.

'Petra?'

'I wouldn't marry him tomorrow. Not tomorrow. No.'

'Good girl. You will see that actually, it's nothing to do with the love, or lack of, that he had for you. Ultimately, you'll see that you didn't really love him enough to be with him for good anyway. The more you doubt someone's love for you, the harder you work at trying to secure it. It's bizarre. Perhaps you set out to see if you could be the one for him without stopping to truly consider whether he was the one for you?'

'Oh, Luce.'

'He's not worth your tears, my darling. And the person worthy of you won't make you cry like this. I promise. Phone Eric first thing because you'll feel very unsure again when you wake up. So phone him. OK?'