Rock & Gem Kids is a monthly feature that offers articles, puzzles, and a quiz with prizes for junior rockhounds.
1. Black zinc sulfide, which has a high iron content, is called marmatite or, informally, “black jack” .
2. Eurypterids belong to the sea scorpion family, but were more closely related to horseshoe crabs.
3. Sphalerite is the principal ore of zinc.
4. Three minerals that come in the dendritic form are (any three): copper, silver, gold, pyrolusite .
5. Double refraction is an optical property of Iceland spar.