She Tai Cui is a type of jade found in inner Mongolia. It has several layers and these are made from one of the outer layers. They have several colors, are not polished and can be "grown" by rubbing them with your hands (with or without oil). You can check the "lollipop" model for a difference between the different state of the jade.
When you receive your piece, it may look dusty and dry as it absorbs and dries humidity, not to worry it is normal. You just need to either "grow" it or dump it in water and let itnkeep company to your fishes. If you do not have patience you can use some oil to keep it in it's polished form. However oils tends to absorb dust so... it's up to you! I personally use it as a hand scrubber so that it's almost wet all the time and is being "grown" at the same time. Use it after you've rinsed off your hand soap!
Weight approx 127g
Size check pics