Feeling slightly guilty, Ruby rushed her meal and then Mrs B showed her to the room Hermione used as a workshop. It was tucked away behind a door at the far end of the corridor, which turned out to be steps leading down to a cellar. Once she reached the bottom of the steps, Ruby looked around and her eyes stretched wide with amazement. A multitude of gas lights made the vaulted room as bright as day, illuminating the long trestle workbenches along the walls, each covered in strands of gold and silver that glinted in the light. Hermione was sitting at one of them with a glass eyepiece in her eye working on something, and as Ruby drew closer she saw that it was a ring.

‘Ah, here you are.’ Hermione looked up as Ruby stopped beside her. ‘I was just choosing a jewel for this mount. Which one do you think suits it best?’ She gestured at three different-coloured jewels gleaming on the table. ‘Do you know what these jewels are?’

Ruby licked her lips. ‘That one is an emerald.’ She pointed to the green one. ‘That one is a diamond, and that one’ – she pointed at the final stone – ‘is a sapphire.’

‘Very good. And which one do you think has the most value?’

Ruby’s brow furrowed as she tried to remember what Maddie had told her. ‘It’s the diamond, I think.’

‘That’s correct. But did you know that not all diamonds are worth the same?’

When Ruby shook her head, Hermione said, ‘You grade a diamond by its cut, clarity, colour and carat.’

Ruby nodded, remembering now that Maddie had told her this.

‘A good diamond should be white with no tint of colour, and it should have no carbon inclusions,’ Hermione went on. ‘And the facets, or the cut, must be exceptional, which is where the master craftsmen come into play. Of course, it is rare to come across an internally flawless diamond so minor inclusions are acceptable provided they don’t detract from the stone’s beauty. Also, you will always find that one perfect diamond of a good size will be worth much more than a number of smaller stones. Diamonds are measured in carat weights and the larger the diamond the more it will be worth. People will pay thousands of pounds for such a stone.’

Ruby was finding the talk fascinating: there was so much more to it than she had realised, but then her eyes settled on some drawings and she was instantly distracted from what Hermione was saying.

‘Did you do these?’ she asked in awe.

Hermione nodded. ‘Yes, every year we try to introduce new designs into our shops and these are some of my ideas for the next season. Hopefully they will be transformed into brooches.’

There was one of a bird with its tiny wings in flight, another of a leaf and yet another of a flower bud just opening.