Hi, I would Exercise caution!
Last year I bought a 0.7 carat diamond ring from Al Suliman (Hyatt Plaza) but they didnt give me any certificate (just a lousy receipt with minimum details).

to add insult to injury, few months later, i found a full 1.0 carat much better designed ring in Dubai and bought it for QR.500 less that that of Al Suliman.

Dubai has more jewellers and competition between them made price more transparent. Plus they provided me with Full valuation certificate.

So, be careful when you buy here in Doha.