Lobe coral. These are smooth and rounded and look yellow-green when seen in the water on bright sunny days. Sometimes they form Christmas tree-like structures; but mostly they form crusts over the rocks. They might not look too impressive, but these corals can withstand breaking waves. Porites lobata.

Lavender Rice Coral. If you see a bright purple coral coating the rocks, you’re probably looking at Montipora flabellata.

Lace Coral. This coral forms small, delicate branched structures in protected, calm areas. Look closely and you might find structures that look somewhat like two hands, palms together, with fingertips touching. A tiny female crab lives inside each of these structures; the male remains hidden deep in the branches, so this coral is also called the Harem coral. Pocillipora damicornis.

Cauliflower coral. When it’s alive and healthy, this coral looks like a tan-colored head of cauliflower, usually standing all by itself. This is a rugged coral often found where there are waves. Pocillopora meandrina.

Table Coral. These corals form flat-topped structures. Lucky you if you ever get to see one alive in the water, because they are not found in the main islands of Hawaii, even though this is the most abundant coral in the world. So, if you see these alive while you’re snorkeling, you’re either in the Northwestern Hawaiian Islands or in some other tropical Pacific island chain Acropora cytherea.

Cup corals. Look for fist-sized clusters of bright orange tubes when you are in calm waters, or when you look under protected rocky ledges or on the inner entry walls to underwater caves. Tubastrea coccinea.

Rice coral. Think of rice covered with shoyu when you look for this coral. If you find it in calm waters, you’ll probably see that it has formed branches as well as rounded plates. Montipora capitata

Finger coral. When you see lots of fingers of coral all clustered together, you’re probably looking at finger coral. This coral breaks easily, so is usually found in calmer or deeper waters, or where it is protected by other, more rugged corals. Porites compressa.