【Mohs Hardness Pen】The Mohs hardness pen is based on the hardness of 10 different minerals, and materials of different hardness are selected to simulate alternative minerals to create a mineral-like scratch pen, which is used to detect the Mohs hardness of various surfaces. 【Mohs Hardness Tester】Made of PH10 crystal, the value is accurate. There are 10 hardness pens in the box, each one is 130mm long and 6mm in diameter. Made of pure stainless steel, with good texture and exquisite appearance. 【Test Grades】Talc-1, Gypsum-2, Calcite-3, Fluorite-4, Apatite-5, Orthoclase-6, Quartz-7, Topaz-8, Corundum-9, Diamond-10. This hardness tester is suitable for gems, ceramic tiles, floors, glass, mobile phone screens, minerals, concrete, etc. 【Wide Application】Commonly used for Mohs hardness determination on the surfaces of various types of solidified floors, floor tiles, ceramic tiles, concrete floor construction industry, glass, ceramics, marble products, ores and minerals, jewelry and jade artifacts, industrial porcelain. 【Note】Note that the intensity of the engraving should be moderate, neither too light nor too heavy, because the direct engraving method to determine the hardness is damaging to gemstones. This method is generally not allowed to be used on finished gemstones.