Free Gentlemen Prefer Nerds by Joan Kilby Page B

croaked. “What did you ask me?”
    With every slow-motion grind of his jaws, Billson’s gum cracked with a tiny popping sound. “Who had access to the Rose in the past twenty-four hours?”
    She couldn’t tell the detective that she’d let Rolf handle the diamond. The insurance would be void. Grace would be ruined, her shop forfeited to pay for the diamond. “I did, and also Kim, our jeweler.”
    Billson stared at her fixedly with his large mild eyes. “No one else?”
    Maddie wanted badly to swallow but she forced herself not to. “That’s right.”
    “When did you first realize the diamond wasn’t the genuine article?”
    “This morning when I unveiled it.”
    “You can tell that at a glance?” He pulled a plastic sample bag from his pocket containing the substitute diamond. “This stone looks exactly like the description of the Rose.”
    “To an untrained eye, perhaps.” After the police had dusted it for fingerprints Maddie had weighed and measured the synthetic stone so she could supply the relevant details. “The weight is virtually identical, give or take 0.005 of a milligram. But the color of the two stones is slightly different. The synthetic would have fooled most people, but I know the Rose as well as my own face. I knew at once that it wasn’t genuine by the difference in hue and intensity.”
    A spark of interest lit the detective’s bland expression. “What do you mean?”
    “Hue is the shade of pink. Intensity is the strength of the color,” Maddie explained. “Dark pink diamonds like the Rose are extremely rare, hence their high value. The diamond on the pedestal this morning had a slightly lighter tone and a less intense color.”
    “So appearance alone tells you this isn’t a real diamond.” Billson held up the sample bag.
    “It is a real diamond. Synthetic diamonds are grown in a laboratory but they have all the chemical properties of a mined diamond.”
    “Then how do you know this one is synthetic?” he asked with a puzzled frown. “Can you tell by looking at it?”
    “No,” she said patiently. “I did some simple tests in my workshop. A natural diamond doesn’t fluoresce under shortwave ultraviolet light, whereas a synthetic diamond glows yellowish-orange.”
    “Interesting.” Billson tossed the bag casually from hand to hand.
    She flinched as he nearly missed, catching the plastic bag by a corner. “That might be a synthetic but it’s still very valuable.”
    “We’ll take good care of it, don’t you worry.” Billson pocketed the bag. “Who had access to the Rose besides you?”
    He’d already asked her that. Was he trying to trip her up? “No one.”
    “You didn’t take it out to show anyone?”
    Maddie hesitated then, remembering that he’d already questioned Grace. “I did show it to a colleague, Dr. Rolf Hauzenegger, a highly respected diamond expert from the University of Johannesburg. I have a workshop and a small lab at the back of the store. Under my supervision he examined the gem under a microscope last night.”
    “Could he have substituted the synthetic stone for the real one when you weren’t looking?”
    “Absolutely not. I was with him every second.”
    Billson wrote a few lines in his well-thumbed notepad. “You say he’s from Johannesburg. How well did you know him?”
    “Not well,” Maddie admitted. “But I’ve followed his research for years. I met him in person for the first time on Tuesday.”
    “Where? Under what circumstances?”
    “We met for coffee a few blocks from here.”
    “And you saw him again last night at the shop?” Billson suggested. “How long was he here?”
    “The first time—” She broke off, aware her story was getting complicated.
    “The first time?” Billson prompted.
    “He arrived and we went out to dinner,” Maddie explained, trying not to wipe her hands on her dress. She had no reason to feel so nervous for herself or Rolf. They were both innocent. “Afterward we came back to the workshop