Das Gold ist teuer.

In German, names of materials are often used with the definite article, especially when speaking generally about the substance as a whole.

So das Gold ist teuer means gold is expensive.

German can sometimes also omit the article in other contexts, but with a sentence like this, das Gold is very natural.

• das Gold = the substance gold
• compare English, where we usually just say gold

Every German noun has a grammatical gender: masculine, feminine, or neuter. Gold happens to be neuter, so it takes das.

You usually have to learn the gender together with the noun:

• das Gold
• das Silber
• das Eisen

The gender is grammatical, not logical. It does not mean gold is somehow neutral in meaning.

Because the subject is singular.

• das Gold = singular
• so the verb is ist = is

If the subject were plural, you would use sind.

Examples:

• Das Gold ist teuer.
• Die Ringe sind teuer.

Because teuer comes after the verb ist, so it is being used as a predicate adjective. In German, predicate adjectives do not take adjective endings.

• Das Gold ist teuer.
• Der Ring ist teuer.
• Die Kette ist teuer.

Notice that teuer stays the same.

But when the adjective comes before a noun, it does take an ending:

• das teure Gold
• ein teurer Ring
• eine teure Kette

It is a basic subject + verb + adjective sentence.

• Das Gold = subject
• ist = verb
• teuer = predicate adjective

This is very similar to English:

• Gold is expensive.

German main clauses usually put the conjugated verb in the second position, and that is exactly what happens here.

In German, all nouns are capitalized, so Gold must be capitalized.

Das is capitalized here because it is the first word of the sentence. If it appeared in the middle of a sentence, it would normally be lowercase:

• Das Gold ist teuer.
• Ich glaube, dass das Gold teuer ist.

Teuer is usually pronounced roughly like TOY-er, but with a German sound, not exactly like English.

A simple learner-friendly approximation is:

• teuer ≈ TOY-er

More carefully, it is often heard as two syllables:

• teu-er

The eu combination in German is pronounced like oy in boy.

Usually, yes. In this sentence, teuer means expensive or costly.

It can also sometimes imply that something costs a lot in a broader sense, depending on context. But here the normal meaning is simply:

• Das Gold ist teuer. = Gold is expensive.

Yes, but the grammar changes depending on how it is used.

As a noun, Gold means the metal:

• Das Gold ist teuer.

As a color word, German more often uses golden or goldfarben in many contexts:

• ein goldenes Kleid = a golden dress
• eine goldfarbene Uhr = a gold-colored watch

So in your sentence, Gold clearly means the metal, not the color.

Sometimes you may hear article-less material nouns in certain contexts, but for a general statement like this, das Gold ist teuer is the standard and most natural choice for a learner.

So if you want a safe, correct sentence, use:

• Das Gold ist teuer.

Yes. Das Gold is the subject of the sentence, so it is in the nominative case.

For neuter nouns, the definite article in the nominative is das:

• nominative: das Gold

Since Gold is the thing that is expensive, it is the subject, so nominative is the right case here.