Both types of jade are harder than a knife blade, fine-grained, translucent and colored in many shades of green, tan and brown. In a few cases, color can be a help. Very pale to nearly white jade is almost always nephrite. More boldly colored jade such as vivid malachite green, purple, blue or bright red is almost always jadeite. The colors are due to trace element impurities, such as iron, vanadium or manganese.
Some useful tests help distinguish jadeite from nephrite.
A streak plate has a hardness of 6.5. Jadeite is harder than a streak plate, while nephrite is softer. Thus jadeite will sink in liquid methyl iodide, while nephrite will float. Jadeite will fuse relatively easily when hit with a blow torch flame, while nephrite will fuse only with great difficulty. There are also subtle differences in appearance.