The Colla Corii Asini should be yellow and transparent like amber color, and the light is black like lacquer for the real one. The real one has no skin odor, summer is not wet and soft. Fire test: take a sample of a small amount of burning in the crucible, the first burst, then expansion and melting white smoke, a strong aroma of sesame oil, ash residue black, loose quality, was a piece or lumpy, not with the crucible adhesion; water test: boiling dissolved, the solution was light brown-red, turbid, and white substances precipitation, the liquid surface of the oil droplets, take the gum dissolved in water, the liquid is clear, turbidity; beat: hand-held force to beat the desktop, the debris The section was brown, translucent, no foreign matter is true, if you tap the soft and not broken, it is suspected of being a fake.

Collagen forgeries a cowhide glue, hard and unbreakable, burning a strong cloudy odor, water test solution without oil droplets on the surface; second is a miscellaneous glue, burning soybean oil aroma, water test solution was dark gray brown-red, a few oil spots on the surface; third is the bone glue, the surface is opaque and lusterless, there are bubbles caused by the small holes, the side of the wrinkles are irregular, hard and unbreakable, the gas is slightly smelly; the fourth is gelatin class, smooth and shiny, brittle. Smooth and shiny, brittle, gas or ink-like odor. After the fire test into a white flaky powder, non-adhesive.

In addition, Colla Corii Asini solution does not agglutinate after 4 hours of standing, the pseudo solution agglutinates into a paste.

In addition, the turtle gum and deer gum appearance and gum similar, should also be identified: turtle gum, the surface of brown slightly greenish, above the yellow "oil head", the light is clean as amber, hard; deer gum, the surface of the black-brown, translucent light, one side of the yellow-white porous layer, brittle and fragile, reddish-brown section, with a glassy luster. With glassy luster.