Microcracking in impact-damaged Westerly granite and Karelian quartzite based on evidence derived from fractoluminescence and acoustic emission

• Acoustic emission and fractoluminescence from impact loaded rocks were detected.
• Amplitude–frequency responses of light and sound emissions were analyzed.
• Crack lengths were evaluated from the amplitude–frequency responses.
• Interplay between inter-/intragranular cracks was observed on damaged surface.
• No intragranular cracks were detected in the bulk of samples.