'Crystal' was a British deception undertaking in the Western Desert to secure the maximum tactical benefit from the arrival of US M3 General Grant medium tanks in British service by persuading the Axis powers that this new armour’s debut was being delayed by ammunition problems (March/April 1942).

The first M3 tanks had reached North Africa in November of the previous year, and 'Crystal' was designed to lull the two Axis powers into a failure to create the earliest possible riposte measures through the dissemination of rumours that most of the new tanks were being used only for training until such time as a solution had been found for their ammunition problems. 'Crystal' was terminated on 26/27 May 1942, when Generaloberst Erwin Rommel launched elements of his Panzerarmee 'Afrika' in the 'Skorpion' operation to retake the Halfaya Pass, lost to the British 'Brevity', and the result of 'Crystal', if there was any, is unknown.