These crystals were used in TBS transmitter/receiver equipment. Although not easily seen, these crystals used a ceramic holder.  The holder was also made with bakelite.

Examples of receive and transmit crystals. These crystals were donated to HMCS HAIDA by John Forster. (Photo by Jerry Proc)

TBS crystal closeup. (Photo by Jerry Proc)

Dimensions: 1.5 in wide x 2 1/8 in high x 0.75 in thick.
Holder material = ceramic or bakelite

Blue example above = 65.340 MHz receive.
Red example above  = 72.500 MHz transmit.

The crystals are truly of battleship-grade construction and even includes anti-tampering wire.  A piece of stranded wire threads its way through three holes in the cover screws. The loose ends are then sealed with lead seal which bears the letters “RCA”. Within the triangle formed by the wire, there is putty like material with the letter V embossed. This is the factory sealed adjustment which allows the crystal to to trimmed to the exact operating frequency.
 

This diagram illustrates the principle of the frequency adjusting screw of a crystal. (Image courtesy RCN)

This is the how the frequency adjustment mechanism looks in a  crystal. The spoke-like springs connect to the banana jacks with braided wire. The holder's cover is the part at the left. (Photo by Jerry Proc)

TBS crystal - USN Navy type in bakelite holder. Donated to HMCS HAIDA by John Forster. (Photo by Jerry Proc)

Credits and References:

1) John Forster <jfor(at)quik.com>
2) BRCN 5422 Electronics Fundamentals , RCN 1952

Aug 8/08