The video contain about the internal world (Inclusions) of different types trip during formation. Such rutile, tourmaline needles etc.
The below video is about the petroleum inclusions in quartz , from Baluchistan, Pakistan.
Glass (Lead) infilling
External: Open cavities (usually on pavilion), filled with glass for a better looking stone (seals cavities, adds weight). Internal: Traces of glassy residue in fractures after heating may be found as a by-product of the particular heating process used. (Stable).
Detection: Magnification. Differences in luster between glass infilling and stone plus possible bubbles in filling and blue orange flashes.