Quartz: Manufactured product from loose quartz, binder and pigment
Pros/cons:
Highly durable
Scratch and stain resistant
No sealer necessary
Holds up to chemicals
Low maintenance
Expensive
Not easy to repair
Not heat resistant over 300 degrees Fahrenheit, though some say ok for hot pots and pans
Stands up to abrasive pads and serrated knives according to consumer reports
Available in wider range of colors than quartzite because pigment can be added to it.
Beware of honed quartz as it shows stains and marks more easily than non-honed quartz
Permanent ink is an exception to stain resistance. Protect surface when using Sharpies.
How to clean and maintain quartz:
Wipe with a damp cloth
Clean counter with soap and warm water daily, if possible
Scrape off dried gunk with a plastic scraper like a putty knife
Do not use abrasive cleaners (nor should you need to)
No sealant necessary