How to distinguish titanium dioxide is real or not?

Physical method:
The easiest way is to compare the feel, fake titanium dioxide is smoother, and real titanium dioxide is astringent.
If you wash with water, if you get a little titanium dioxide on your hands, the fake one is easy to wash off,  the real one is not easy to wash off.
Take a cup of water, throw the titanium dioxide in, the ones that float up are real, and the ones that settle down are fake (if it is an activated modified product, it will not work).

Chemical method:
Mixed with light calcium or heavy calcium: Adding dilute sulfuric acid or hydrochloric acid, the bubbles can make the clarified lime water cloudy, because calcium carbonate will react with acid to produce carbon dioxide.
Mixed with Lithopone: Add dilute sulfuric acid or hydrochloric acid to smell of rotten eggs.
Made into latex paint, add iron, if the color is red, indicating that the poor hiding power is fake or poor quality titanium dioxide.

There are also two better methods:
Using the same PP+30%GF+5%PP-G-MAH+0.5% titanium dioxide, the lower the strength, the more real the titanium dioxide (rutile).
Choose a transparent resin, such as transparent ABS+0.5% titanium dioxide, and measure the light transmittance. The lower the light transmittance, the more real the titanium dioxide.