What's been deposited in four squares of this puzzle, expressed both by name and by symbol

Question:

Answer:

METALLICELEMENT

Length:

Similar Crossword Questions:

Hint to filling in four squares in this puzzle
Mail conveniences ... or a hint to eight squares in this puzzle
Company "sorted" in this puzzle's circled squares
Work by Sir Edward Elgar hinted at by this puzzle's circled squares
Question asked by a customs officer or a kid on Christmas ... with a hint to this puzzle's circled squares
Common interface that is a model for several squares in this puzzle
Locale for this puzzle's shaded squares
Type of gear on which the letters in this puzzle's nine theme squares are arrayed
Puzzle with number squares
Geographical features ... or what the circled squares in this puzzle represent
How this puzzle's black squares are arranged
This puzzle's theme, whose first notes are indicated by shaded squares
Secret get-together, or what occurs literally in each of this puzzle's circled squares
Web concerns ... and based on six familiar names hidden in rows 1, 4, 12 and 15 of this puzzle grid, what the black squares in those rows symbolize
Close associates, and a hint to this puzzle's highlighted squares
Its symbol is a globe composed of jigsaw puzzle pieces
What eight squares in this puzzle contain, thus creating a cipher key
Trains, in a way, and the key to 18 of this puzzle's black squares. (Ones that begin with the keyword are asterisked. The others are for you to discover.)
Daily crosswords, to puzzle pros (so-called from the number of squares per side)
Complete set of 12 shapes formed by this puzzle's black squares
Like aleph in the central black squares of this puzzle's grid
79, for the chem. symbol at the heart of the four longest puzzle answers
What's revealed by connecting the special squares in this puzzle in order
Like some crossword-puzzle squares
What the highlighted squares in this puzzle represent