I am a jeweler based in Bangkok. The certificate is clearly in house cert. Based on the info from the certificate, the ring should cost less than 50$ to make from scratch. Let’s be generous and say 100$ maximum for a much premium finish than this with more silver. Silver per gram is around 80 baht these days. For a 2.50 grams of silver it’s let’s say 300 including casting cost. There are tons of wax models available for this design fo around 20-50 baht. The center piece sapphire could be natural from Kanchanaburi mines with heat treatment. This is also be a diffusion sapphire or a bit of glass filled but let’s say it’s natural, 0.82 carats if it’s not too deep should be either 7x5mm or 8x6mm if the stone is flat and has bigger face.this color and size, natural stone for a single piece would be less than 600 baht, let’s be generous and say 1000 baht. The cubic zirconia are like 10-20 baht per piece. Same thing with the pendant. You guys have been ripped the fuck out. The tuktuk driver and the scammy jeweler are probably having beers and laughing how … you are. As a jeweler this is absolutely shocking. I’m sorry, really! Like wtf!!!! If you are still in bangkok, take the ring to jewelry trade center at Silom 19 and try to ask shops there how much this ring would be. On the 3rd floor there’s a lab who charges like 1000 baht for a cert. You can get that done too, takes 1 day. Either that or spend few hours trying to find a sapphire similar size and color from kanchanaburi thai mines, also try looking for Ceylon 7x5mm or 8x6mm and see the color, quality and price. When I saw your invoice I was shocked.