Tin pest related problems such as tin whiskers. At 13.2 °C (about 56 °F) and below, pure tin transforms from the silvery, ductile metallic allotrope of β-form "white tin" to the brittle, nonmetallic, α-form "grey tin" with a diamond cubic structure. The transformation is slow to initiate due to a high activation energy but the presence of germanium (or crystal structures of similar form and size) or very low temperatures of roughly −30 °C aids the initiation. There is also a large volume increase of about 27% associated with the phase change to the nonmetallic low temperature allotrope. This frequently makes tin
Christmas gift (exclamation) also in southern Pennsylvania, Ohio Valley, West Virginia, and later in northeastern Texas as a simple greeting and recognizing the birth of Christ as a gift. A variant of the tradition is "Christmas Eve gift". The tradition is similar to the "Christmas gift" tradition, but occurs on Christmas Eve. The person being told "Christmas Eve gift!" is expected to present the person saying it to them with a small present, traditionally candy or nuts. The Dictionary of American Regional English traces the first written uses of this version to 1954. Christmas gift (exclamation) "Christmas gift" is an exclamation traced back