THE MINERAL BLODITE

• Chemistry: Na₂Mg(SO₄)₂ - 4H₂O, Hydrated Sodium Magnesium Sulfate.
• Class: Sulfates
• Uses: Only as mineral specimens.
• Specimens

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Blodite, which is also spelled bloedite, forms in marine and non-marine (lacustrine) evaporite deposits. Evaporite minerals are geologically important because they clearly are related to the environmental conditions that existed at the time of their deposition, namely arid. They also can be easily recrystallized in laboratories enabling sedimentologists to obtain their specific characteristics of formation, such as temperature, solution concentrations, etc. Blodite also forms as an efflorescence on cave and mine walls. An efflorescent mineral is one that forms literally out of thin air, as a "precipitate" of sorts from fumes concentrated with the mineral's chemical makeup. Crystals of blodite are scarce, but well formed crystals can show an intricate, multi-facetted, monoclinic form. Specimens of blodite should be stored in a sealed container as they can dry out and crumble.

PHYSICAL CHARACTERISTICS:

• Color is white, colorless, gray, yellow. red, green or blue-green.
• Luster is vitreous.
• Transparency: Specimens are translucent to transparent.
• Crystal System is monoclinic; 2/m.
• Crystal Habits include granular, earthy and encrusting masses. Individual intricate, multi-facetted, prismatic crystals are uncommon.
• Hardness is 2.5 - 3.
• Specific Gravity is approximately 2.2 - 2.3 (light for translucent minerals).
• Streak is white.
• Other Characteristics: Salty taste.
• Associated Minerals include halite, epsomite, alunite, thernardite, trona, sylvite and other more rare evaporite minerals.
• Notable Occurrences include the type locality of Chuquicamata, Antofagasta, Atacama Desert, Chile as well as Soda Lake and other California sites and Coconino, Arizona, USA; Germany; Russia; Austria; Poland and India.
• Best Field Indicators are associations, density, crystal habit, taste and environment of formation.