identify them only. when we have three samples how can I decide which one is magnrtite or hematite or iron clay power. I am working in quality control and we have so many samples of ores I am looking for easy way to identificate them
It will depend on the particle size distribution of your samples, but you can use the differences in their physical properties to identify them. Some will work better than others.
Color
Hematite (red) and magnetite (black) have distinct colors. The clay may be similar to hematite, but it will depend on mineralogy. A good digital camera and good lighting may give you enough information to reliably identify.
Density
The minerals have different densities. Hematite and magnetite have similar densities, but the clay will probably be much lower.
Magnetic Susceptibility
Magnetite is the most magnetic of the three. A hand magnet with the correct magnetic flux density should help you to identify magnetite with a high degree of certainty.
Some combination of these three properties may help you to do a quick identification.