The Stila Kajal liner is like a kohl liner, where it's a very soft texture and formula that is suppose to be richly pigmented. The product goes on so easily and smoothly, I especially love using it to smoke out my lash liner. You barely have to apply any pressure for the perfect color and application.
Smokey Quartz is a dark, charcoal grey that is quite beautiful. It's different from just a jet black liner, so it does add a bit of depth to your eyes. It tones down the intensity of a smokey eye look a bit, so it's a change from just a black smokey eye.
Because the product is so soft, you can roughly apply the product on your lash line and then smudge it out with a pencil brush. Or, you can take an angle brush and pick up some product from the liner, and use the angle brush to create a more thin and precise line.
The quality of the liner is amazing and really lives up to the claims. However, you do have to let the product set a while before expecting it to be smudge proof and long lasting (it always helps to set with a powder).