Jarosite Is a type of rock that can form in an acid rich lake or a hot spring enviornment, Color - Amber yellow or brown Crystals - Transparent to translucent Crystals are somewhat scarce and small, more commonly granular. Rhombohedral crystals - combination of two trigonal pyramids

This rock dubbed "Peace" rock shown in the black and white photo have very high sulfer content deep inside the rock. The observations show the rocks contain significant amounts of olvine, pyroxene, and magnetite, all of which are common in some type of volcanic rock,

Olvine

Orthrombic Structure

Olivine - Is a magnesium Iron silicate which is one of the most common minerals on Eath. It has been found on mars. Shows evidence of water. Crystals - Orthorhombic system.

Gabbro - Dense, greenish, or dark colored rock that may contain olvine, copper sulfates, and other minerals. Crystals - Coarse grained with crystals in the size of 1mm or greater. Equigranular in texture. Shows evidence of wtaer.

Pillow Basalt - A type of basalt that forms from cooling underwater. Glassy crust. Size - from 10cm to meters Microbial activity may alter chemical composition of the rock, microbial life grows on this basalt. Forms under water.

Obisidan

Igneus Rock - Rocks formed by solidification of magma. May be crystalized or not, over 700 types. Phaneritic - Cools slowly, very large crystals can be seen by naked eye. Porphyritic - Quickly cooled, causing a glassy texture. Either by being shot into air or water Such as Obisidan which is formed when the magma cools so quickly that the magma doesn't have enough time to form any crystals, thus forming a glossy texture

Halite - Forms in vast like where the water evaporates and leave sedimentary behind. It's chemical composition is NaCl. It occurs when vast lakes of sedimentary dry up in lakebeds Crystals - Predominatly cubes

Calcite - Can be a chemical or biochemical calcium carbonate. Viens can be formed when it is in the presence of a hot spring. Calcite is the primary element in shells of marine organisms such as Bivalves, algae, sponges.