Identifying Markings on Vintage Silver Ring with Stones - Expert Analysis

Question
Dear sir, at an auction I have acquired a silver ring which holds, embedded in a silver frame, a flower motive of 5 differently coloured petal-shaped stones (yellow, light blue, deep red, light moss-green and light purple) with a total of six smaller colourless stones, one on top in the centre of the 'flower' and the others in between these 'petals'.

My question is about the markings on the inside of the ring on the opposite side of the '925' emblem. What I can see by reading with a loupe from left to right are the letters AG roughly engraved, then something in the form of a right triangle which has the right angle on the left and up-side - the triangle is considerably smaller than the letters - then an x-shaped mark of the same size as the triangle - because its so small the lines of the 'x' are relatively 'fat'. Would you perchance be able to tell me what these markings may mean and what kind of stones could be embedded? I can see a star-shape through the top of the colourless stones, so I guess they are not diamonds. Thank you for your answer in advance!
Violet

Answer
Hi Violet,

Well the only thing i cansay for sure is the "925" means it is a sterling silver ring. So the rest is just a guess. The markings inside are more than likely the maker of the ring. they tell nothing abot the stones. Since it is a silver ring most likely the stones are semi-precious and no diamonds. The yellow could be citrine, light blue could be blue topaz, deep red maybe garnet, moss green could be adventurine and light purple maybe amethyst. The cololess are probably quartz. But they are all guesses since I have not seen them and even come close. It sounds very nice and I'm sure you will enjoy it.

Peter