Iron Blueberries
MER mission scientists have found hematite in the small spherical "blueberries" embedded in the rock outcrop near Opportunity's landing site. They speculate that the broad plain surrounding Eagle Crater, where the rover landed, may be littered with blueberries.

Berries Near Spirit's Serpent?
The iron-rich spheres found at the Opportunity landing site have a counterpart halfway around the planet, according to recent trenching images taken from the ancient lakebed. At a transition region near a dune called Serpent, aggregates of fine dust have formed tiny balls, although their composition is not likely iron-rich.

El Capitan
The Mars' Opportunity site offers its latest drilling target, a rock called El Capitan after the Texas mountain and spanish term for captain. The rock interests geologists because two distinct textures and colors point to a mixed origin, which the rover is well-equipped to drill in the center of both types.

The Big Dig
Both rovers have started to dig into the martian surface. By locking all but one wheel, the rover is equipped to scoop out about a half-wheel diameter (20 cm). By then turning its instrumented robotic arm on the hole, the rover is able to look below the top layer in unprecedented ways.

Touch and Go Days
Acting as a surface surveyor, the twin geology labs have their days that are called 'touch and go'. These traverses typically mean that the rover picks a target, then studies its thermal, chemical and microscopic profile. As both rovers gear up for travel, the Spirit rover drilled into its first rock--the first chance to get inside the geology of another planet.

Mars, The 'Little Round Guys'
The Opportunity rover sent back microscopic images of the martian soil. Intriguing spheres found on top of the crater floor has scientists interested in seeing what's inside.

Opportunity Finds Martian Layer Cake
Geologists on the rover science team are excited by the discovery of fine layering in the rock outcrop that sits directly in front of Opportunity. One possibility is that the layers are sediments deposited billions of years ago by liquid water.

Depth to Bedrock, Zero
The Opportunity landscape offers enough geological gems that science teams already have a rough idea of where they want to explore, only hours after the first pictures arrived. The scientists rated the Meridiani site as their first choice prior to launch. So far they have no reasons to be disappointed, having their rover land in a crater, within a couple days drive to bedrock, and a mission plan to go to another bigger crater with a bright rim.

A Bizarre New Mars
The first color images from Meridiani, Opportunity's landing site in a flat, volcanic plain, suggest fine-grain soil and the first bedrock ever seen on Mars. The significance of bedrock to geologists can be compared to a history book of the planet, with its binding still ordering the pages to be read. This differs from the scattered page order that other site geology may have offered, because crater impacts and surface flows transport those materials.

Little Green Martian Mineral
The Spirit rover's first soil analysis reveals some puzzling features about Gusev crater. The region seems to contain the greenish mineral, olivine, which usually is considered water-reactive and volcanic in origin. For olivine to be found in the soil may point to rock formation during a drier period in martian history. A second puzzle is why the soil seems so crusty. After the rover arm pressed soil down, the top layer of dust hardly moved, a finding that suggests something may be binding the dust like some type of salt or thin cement.