Even with a magnifying glass, the visitors could barely spot the unusual spider — just a quarter of an inch long — that was resting on a kawau (native holly) leaf in Hawaii Volcanoes National Park.

Endemic to Hawaii, the happy-face spider sports a pattern on its body that resembles the broad smile of a clown. It belongs to the family of arachnids (Theridiidae) that includes the infamous black widow, but it doesn’t have the toxic bite of its feared cousin.

"Happy-face spiders like to live on the underside of leaves at cool, lush elevations ranging from 3,500 to 6,000 feet," said Garry Dean, a guide for Hawaii Forest & Trail (HFT), a Kona-based company that specializes in nature tours for small groups. "The forest that surrounds Thurston Lava Tube in Hawaii Volcanoes National Park is at 3,900 feet, which makes it the perfect home for them."

Dean has often seen happy-face spiders on his own, but a stop at the lava tube during a tour he was leading in the park in November was the only time he has been able to find one to show to visitors.

"The spiders are tiny, and they blend in with the leaves, so you need a magnifying glass to see them," he said. "That’s one of the reasons I enjoy taking guests on the Kilauea Volcano Adventure, I point out amazing things that they would probably miss if they were on their own."

Dramatic scenery, including lava flows dating back 700 years, make that tour one of HFT’s most popular offerings. Stops are somewhat flexible, with the guide taking into account the interests and physical abilities of the participants.

"We run the tour daily, and during any given week they could all be different depending on who’s in the group," said Dean, who holds a degree in geography from the University of Hawaii at Manoa. "Over the past 14 years, I’ve guided the tour hundreds of times, but I never get tired of doing it because every plant, bird, animal and volcanic formation has a fascinating story to tell."

Kilauea Volcano’s current eruption began in January 1983. The warm vapor rising from numerous steam vents hints at the existence of 2,000-degree Fahrenheit magma chambers nearly a mile below the surface.

"Groundwater seeps down over rocks that have been heated by the magma," Dean said. "The resulting steam comes out through the vents."

Pit craters are formed when magma rises but doesn’t break through the surface. Instead, a circular depression is formed when the ground collapses on itself. That could happen suddenly, all at once, or over the course of many years.

Hiiaka’s Crater, named after the sister of Pele, the Hawaiian volcano goddess, is a pit crater that measures about 350 feet deep and a quarter-mile in diameter. Surrounding it are expanses of rough aa lava and smooth pahoe­hoe lava; bizarre lava trees, formed when molten lava engulfed trees and solidified around them; ohelo berries, a relative of blueberries and cranberries that’s a favorite of Pele; and the ohia tree’s crimson lehua, her preferred flower.

"One of the interesting things about the ohia is that it can hold its breath," Dean said. "When an eruption occurs, it releases carbon dioxide, sulfur dioxide and other poisonous gases. To avoid taking those in, the ohia closes its stomata, the microscopic pores on the bottom of its leaves, and waits for the eruption to stop or the wind to clear the air before it opens again. I think it’s the only tree in the world that holds its breath, so to speak, because of volcanic gases."

Equally fascinating are Pele’s tears, created when airborne lava droplets cool quickly and fall to earth as ebony teardrops; Pele’s hair, formed when the wind or explosive eruptions stretch bits of molten lava into fine strands of glass; and olivine, the sparkling yellow-green crystals that result when the iron, silicon and magnesium in lava combine in just the right quantities.

Even such small, delicate objects provide big clues about Hawaii’s origins. The islands were born from volcanic eruptions that left barren lava fields. A few plants eventually appeared in those fields, growing from seeds and nutrients carried by the wind. Given enough time and rainfall, more and more plants and trees took root until there was a forest.

"The forest thrives until another lava flow comes and destroys it," Dean said. "The land is new, the slate is wiped clean. And the cycle of life on an active volcano starts all over again."

Cheryl Chee Tsutsumi is a Honolulu-based freelance writer whose travel features for the Star-Advertiser have won several Society of American Travel Writers awards.