It's a logo of a Thin Test Tube. The beaker has a dark outline and is white in the middle. The beaker is small and has a liquid inside just past halfway.
This Experiment icon is made in flat color style
. This format was developed by Icons8 designer team and became immensely popular for use in web and mobile applications. Feel free to download this icon in PNG format for free, or unlock other formats for $5. Unlike other icon packs that have merely hundreds of icons, this monster icon pack contains 5,900 icons, all in the same style and quality.