The makers mark can bring a lot of money but when looking at the stone itself, I've sold a several pieces of high dollar turquoise. The high dollar is achieved from specimens that are pure blue and do not have ANY matrix or other minerals.
Geologists and curators have explained to me that many of the turquoise mines have been exhausted and the remaining material has a high matrix content, like the cabochon shape in your ring. Many folks like the blend of turquoise and matrix, but the real money is in the scarcity of solid, pure blue. Additionally, the hue of the blue (more blue than green) also adds to the value.
I've sold (wholesale) solid blue pebbles (raw and uncut) the size of a nickle for $20 and blue with matrix for $5. If I recall correctly, the most valued piece I sold was acquired from a mine in 1968. It had a mass of 690 grams (21 oz) and appraised for around $3,000. After negotations and commissions, I netted substantially less.
Anyhow, cool stone. If you do find some that are pure blue, I wouldn't count your chickens until the eggs are hatched. China is making boatloads of fake stones. Some are dyed. Some are a mixture of resin and other "stuff".