One of the Gatherers pours clear liquid from a pitcher. When Brull takes the chalice and pours it onto Temarek's face, the liquid is now white.
When Riker and the away team vaporize the nearby duranium scrap metal to block the field of view of the attacking Gatherers, the temperature of cloud of gaseous duranium created would have been 2314 degrees (as Commander Data had just said). The Gatherers who then walked through that cloud would have burst into flames for doing so.