03-29-2016, 09:25 AM
Millions of Hertz (quartz is famously known to be able to vibrate at a steady 3.5MHz). In the case of quartz the induction might be from electrical signal, but I've long forgotten what officially makes crystals vibrate.
A Better Alex (ISTJ): EPRHA → ASC → AM6 → …
A Sexy Alex (ESTJ-T): BIABWS+DAOS → DMSI → …
A Better Alex (ENFJ-T): AM6 → …
A Sexy Alex (ESTJ-T): BIABWS+DAOS → DMSI → …
A Better Alex (ENFJ-T): AM6 → …