Patent ID: 7011887

Claim:
An IT-cut crystal unit comprising: a crystal blank cut from a crystal of quartz along a plane perpendicular to a Y-axis of the crystal of the quartz which is rotated over approximately 34° about an X-axis, and further rotated from the rotated position over approximately 19° about a Z-axis; and excitation electrodes formed on both main surfaces of said crystal blank, respectively, wherein said crystal blank includes first to fourth positions on a peripheral region thereof, said first position being defined in an angular range of 18°±18° from a Z′-axis on a surface of said crystal blank, when viewed from a center on the surface of the crystal blank, said second position being defined in an angular range of 198°±18° from the Z′-axis on the surface of said crystal blank, the third position being defined in an angular range of 108°±18° from the Z′-axis on the surface of said crystal blank, and the fourth position being defined in an angular range of 288°±18° from the Z′-axis on the surface of said crystal blank, said crystal blank has holding positions at at least one set of opposing positions selected from said first to fourth positions.