What is the difference between Khums & Zakat?

Zakat is obligatory (wājib) on ten things:
1. wheat;
2. barley;
3. dates;
4. raisins;
5. gold;
6. silver;
7. camels;
8. cows;
9. sheep [and goats];
10. business goods, based on obligatory precaution (al‐iḥtiyāṭ
al‐wājib).

Khums becomes obligatory (wājib) on seven things:
1. profit from earnings;
2. mined products;
3. treasure troves;
4. lawful (ḥalāl) property that has become mixed with unlawful
(ḥarām) property;
5. precious stones that are acquired by underwater diving;
6. spoils of war;
7. land that a dhimmī1 purchases from a Muslim, based on the
well-known (mashhūr) juristic opinion.

For more details please refer to the Islamic Law book of a jurist