This large piece of jade nicely captures the wide variety of colors found in Washington jades along with the often characteristic shape of many jade rocks.  Jade often wears down into oblong, almost disk like shapes.  I left the edges of this piece untouched as it nicely shows the contrast between the polished faces and the rough mottled outer skin found on jades.

Rock type: Jade, likely nephrite

Nephrite is a metamorphic rock that forms from the metamorphic transformation of serpentines in lower pressure and temperature conditions.  It is an amphibole mineral.

Chemical composition: Ca2(Mg, Fe)5Si8O22(OH)2