A stone could be switched very quickly and 10 minutes is plenty of time. Having said that, my guess is that either you, or that jeweller damaged the stone. Get a second opinion from a reputable jeweller before proceeding.
If indeed it has been damaged, your ring is insured, which is good news. Call the insurance company for further instruction. Tell them you believe it is damaged. It is not worth your while to go into the entire explanation of believing the jeweller did the damage, unless it will make you feel better. But remember, you don’t have any proof that the jeweller damaged your stone.
I chipped a diamond once by hitting it on the side of a door. It was a valuable stone (1.61 ct.). I was sent to a jewellery appraiser. She assessed the damage and submitted the necessary paperwork stating the damage, location and recommendation the stone be replace. In the meantime I was given the option of picking an alternate stone, which was a great deal of fun. This was a huge diamond factory type setting. Bars on double doors and very tight security. Cameras were everywhere.
She brought out many stones. Laid them in front of me and let me pick the one I wanted. I was able to hold many in my hand and exam them under a loupe. Each had a certificate – a all were lovely! (They did try to up-sell me – i.e. I would pay over what the insurance company covered) Within 2 weeks they had reset the stone in my original setting.
Of course, you are given a choice of stone that relects the market value of the stone. If the stone is appraised at (an example only) $25,000.00 – and the true market value of your stone is only 15,000.00 – that is the amount the insurance company will cover. Appraisals are only a guideline and normally overpriced. Incidently the higher the dollar value on the appraisal, the more insurance you pay. I’m telling you this because I am a stickler for detail and if I am paying more for insurance, then I want the appraisal to reflect market value, but I degress.
The only thing the insurance company had me do was fill out their paperwork and have a lawyer add his signature and seal. Once the paperwork was received by the ins. co. and reviewed, I returned to that very interesting high-security building to pick up my ring!
Hassle? Maybe. Fun? – definitely and well worth the effort. (admittedly it was stressful at the time)
Another FYI: This was in Canada
ETA: If it was switched and replaced with a CZ , I have no idea what you should do. 🙁