Crystalline silicon has a metallic luster and grayish color. Silicon is a relatively inert element, but it is attacked by halogens and dilute alkali. Most acids, except hydrofluoric, do not affect it. Elemental silicon transmits more than 95% of all wavelengths of infrared.
Melting point: 1414 °C Boiling point: 3265 °C
A powder is a solid material with a defined size range.