Granite is hard and dense. As such, it is naturally scratch, etch and stain resistant. That makes it suitable for use in kitchens, bathrooms, wet and dry locations. Granite is stable and not overly sensitive to heat and that makes it suitable for fireplace applications.
Quartz is manmade from natural minerals including quartz plus resins and pigments. It is very hard and both stain, etch and scratch resistant. It is vulnerable to heat damage as is not recommend for fireplace applications
Quartzite is a natural stone that is very hard and therefore scratch and stain resistant. It can be used anywhere granite is used.
Soapstone is softer than granite and can scratch easily, but can also be sanded and repaired with no special tools or skills. Soapstone is very heavy and dense and completely non-porous therefore very stain resistant and handles heat like no other stone so it is suitable in kitchens, baths, fireplace and both wet and dry locations.
Marble is soft and vulnerable to scratching, staining and etching and is most suitable for use in bathrooms. It can be used in kitchens but extra care should be taken to maintain its appearance
What is Cheaper? Granite, Marble, Quartz, Quartzite, or Soapstone
Typically Granite will be most cost effective and then move up in price point. Quartz, Soapstone, and Marble will then typically start at about the same range a little higher from granite. While quartzite will start at the higher end of the price range.
What Causes Price Difference?
The short answer to this question is that its the availaity of the stone. The more common the stone, the less expensive it will be. However there are many other factors such as country of origin, density, resin coatings, etc. Quartzite for example is very hard, and therefor difficult and costly to mine from the earth. The higher pricepoint is a reflection of its limited availablity.