Gold and silver jumped sharply yesterday after announcement that Israel had bombed and destroyed an Iraqi nuclear reactor. Both metals lost some of the gain in New York but still closed higher on the day.

With most European markets closed for the Whitsun, or Pentecost, holiday, the dollar held steady at its very high levels.

In London gold closed at $472.50 an ounce, up $11 from Friday's close of $461.50 and $15 higher than the opening. In New York, where gold jumped to $475.50 at mid-day, it eased to close at $462.50, still well up on Friday's close of $453.50. The New York Commodity Exchange settled gold at $462.40, up from $452.

Silver closed at $10.18 an ounce, up from Friday's $9.895, and it settled on the Comex at $10.15, up from $9.895. It had traded up to $10.31 earlier.

The pound, which closed last week at 2 1/2-year low against the dollar, opened in London at $1.9410 there. It closed at $1.9370 in New York.

In Milan the dollar held steady at record high levels, closing at 1,206.05 lire against Friday's 1,208.95; and it closed at 1,205 in New York.

In Tokyo the dollar closed at 228.20 yen, up from Friday's 227.05, and it was trading at 228.05 in New York.