Dr. Youness Khan wrote in his memoirs that he had observed seven different types of glances of the Master.  Here follows an excerpt from Memories of Nine Years in Akka (page 416):

One is the effect of ‘Abdu’l‑Baha’s glance. Not a description of the Master’s eyes; such descriptions have already been recorded by many of the believers, and are all entirely true. Nobody, in fact, could look directly into ‘Abdu’l‑Baha’s eyes. On His arrival in America (as recounted by the members of His retinue), when the optometrist arrived to examine the Master’s eyes he was unable to look directly into them. This matter is well known to those who have attained His presence. …

The effect of His glance, however, is my real purpose.

First, the look of anger, for which “I seek refuge in God from His wrath”. But this look, praised be God, was very rare.

Secondly, the glance of love and compassion. This was His permanent and all‑encompassing glance, bringing joy and delight.

Third, that magnetic, captivating and all‑conquering gaze. On many an occasion in the narrow, dark alleys of ‘Akka, I have observed non‑Baha’is who followed us utterly attracted and captivated by ‘Abdu’l‑Baha, until dismissed by Him. This glance had certain characteristics, which I cannot even begin to describe. With a glance, the kings conquer a realm, With a glance, to the kingdom of hearts you lay claim.

Fourth, the look of satisfaction, which meant, “I am well pleased with you”. This look was the same for both obedient and the rebellious.

Fifth, the gaze which the perceives through divine power the desire of the one beheld. In this state, I felt that if I asked for sovereignty over the earth and heavens, He would grant it to me‑but in that instant one could have no other wish but that which was the will of God I saw this look many a time. Under its influence, one desires suffering in the path of God. Varqá, the martyr, and certain others, hastened to the field of martyrdom under the influence of such a gaze”.

Sixth, the searching glance, so that the one beheld realized that everything in his heart and mind, from past to future, was laid bare before Him. Those secrets and deceit that in man may lie hidden, Before God are clear as daylight, so it is written.

Seventh, and above all, the look that bestows knowledge and understanding. For example, we were witnesses to two individuals who became enraptured with such a glance and received true understanding.