I went to one place that suggested that Quartz will fade in sunlight and that it's priced higher than granite. Homedepot's literature shows both to have the same durability.
Like baseball cards, it's worth whatever you are willing to pay for it but likely less than whatever you paid for it.
Some quartz is sold by the ton. Some is sold by the carat. Amethyst, citrine, Tigers Eye sell for hundreds of dollars. One of my favorites, picture jasper, can sell for more if you can slab and polish it; and find the unique picture in it.
