It appears to be a clear stone with staining from another mineral. Maybe a garnet. The clear stone appears very hard from the conchoidal fracture. The clear stone could be one of quartz, diamond, topaz...sapphire. As most of the gems are harder than a streak plate(unglazed porcelain tile), they will leave no streak and they may scratch the streak plate indicating they are harder than the streak plate which is 6.5 to 7.0 on the Mohs scale of hardness. If you test a specimen, it should be clean and it should be tested in two different places on the stone.
Gemologists do not use this test. It will only give you an idea of how hard the stone is, if it produces a streak, it will reduce the possibilities the minerals could be, narrowing your focus to help identify it.