Quartz Tumbled- 1.1 g

Batch of natural round pebbles (clasts) – Costa Dorada, Spain – Mineralogical and Petrographic Selection
Technical Description of the Batch
This batch consists of a selection of pebbles (continental clasts) collected on the coast of Costa Dorada (Tarragona, Spain). Each piece has undergone a natural process of marine abrasion and mechanical erosion over a prolonged geologic period, resulting in a sub-spherical and ellipsoidal morphology with smooth-polished textured surfaces and no sharp edges.
(Note: The pieces were photographed on a black, moist background to highlight the contrast, the saturation of their natural colors, and the internal structure of their veins).
Petrographic and Mineralogical Classification of the Batch:
The collection offers a representative sample of the region’s coastal geology, highlighting the following lithological families:
Siliceous Rocks (Quartz and Quartzite): Specimens of high hardness (≈ 7 on the Mohs scale). They appear in translucent, milky varieties with iron oxide patinas that impart yellowish and orange hues.
Jaspers (microcrystalline quartz variety): Pebbles with red and ochre coloring due to microinclusions of hematite and other iron oxides. They exhibit a typical concoid fracture.
Plutonic Igneous Rocks (Granites): Phaneritic texture of medium-fine grain. Visible composition of quartz, potassium feldspar (orthoclase), and micas (biotite/muscovite), yielding the characteristic mottled appearance or a "checkered texture".
Metamorphic and Sedimentary Rocks (Limestones/Schists): Secondary fractures sealed by veins of recrystallized white calcite, creating striking structural contrasts on gray and brown matrices.
Technical Data Sheet of the Batch
Geographic Origin: Alluvial and coastal deposits of Costa Dorada, Mediterranean Sea (Spain).
Treatment: None. 100% natural specimens, washed only with demineralized water to remove soluble salts (saltpeter) and for basic biological disinfection. No varnishes, oils, or synthetic waxes.
Condition: Excellent state of structural conservation. No recent fractures or mechanical exfoliation.
Applications: Natural history collecting, educational geology samples, aquatic landscaping (aquascaping), and minimalist or rustic interior design applications.
Total approximate weight: 1.1 kg (1100 grams).
Notice: This description was prepared with the help of artificial intelligence and may contain some errors in the description.