mineral
Quartz geode/drusy quartz cluster
Quartz (SiO₂), with probable feldspar host and minor iron-oxide staining
AI-generated identification · may be incorrectColorless to white drusy quartz crystals with vitreous luster; quartz hardness 7, trigonal crystal system, no cleavage, conchoidal fracture, specific gravity about 2.65. The rounded pink-gray matrix may be altered feldspar or rhyolitic volcanic rock.
Identified More mineral →
Explore Quartz geode/drusy quartz cluster in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Colorless to white drusy quartz crystals with vitreous luster; quartz hardness 7, trigonal crystal system, no cleavage, conchoidal fracture, specific gravity about 2.65. The rounded pink-gray matrix may be altered feldspar or rhyolitic volcanic rock.
Formation & geological history
Likely formed when silica-rich groundwater deposited quartz crystals in cavities or fractures of volcanic rock, commonly during cooling or later hydrothermal activity. Exact geological age and locality cannot be determined from the photograph.
Uses & applications
Used as a decorative mineral specimen, lapidary material, and occasionally in jewelry; quartz is also important in glass, electronics, and industrial abrasives.
Geological facts
“Drusy” describes a coating of many tiny crystals rather than a single large crystal. The sparkling surface is produced by crystal faces reflecting light.
Field identification & locations
Identify by the fine, glittering quartz coating, hardness, and absence of cleavage; quartz will scratch glass, though testing may damage the specimen. Common sources include Brazil, Uruguay, Mexico, Morocco, and the western United States.
