Золото дорого.

Gold is expensive.

Breakdown of Золото дорого.

• дорого: expensive
• золото: gold

Questions & Answers about Золото дорого.

Why is there no word for is in Золото дорого?

In Russian, the verb to be is normally left out in the present tense.

So:

• Золото дорого = Gold is expensive / valuable
• literally: Gold expensive

This is completely normal Russian.
If you were talking about the past or future, you would use forms of быть:

• Золото было дорогим = Gold was expensive
• Золото будет дорогим = Gold will be expensive

What case is золото here?

Золото is in the nominative case, because it is the subject of the sentence.

The basic dictionary form is:

• золото = gold

In this sentence, Russian is simply saying something about gold, so nominative is the expected case.

Why is it дорого and not дорогой?

Because золото is a neuter noun, and the predicate form here agrees with that.

• золото is neuter
• the short-form predicate is дорого

Compare:

• Хлеб дорог = Bread is expensive (masculine)
• Машина дорога = The car is expensive (feminine)
• Золото дорого = Gold is expensive (neuter)
• Товары дороги = The goods are expensive (plural)

So дорогой is not the right form here.