Mineral (Cryptocrystalline Quartz)

Strawberry Quartz

Silicon Dioxide with Hematite inclusions (SiO2 + Fe2O3)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Rose Quartz

Silicon dioxide (SiO2)

Yellow Quartz (Chalcedony/Citrine Pebble)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Milky Quartz (Beach Pebble)

Quartz (Silicon Dioxide, SiO2)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Rose Quartz

Rose Quartz (SiO2 with traces of Titanium, Iron, or Manganese)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Beach Quartz Pebble

Quartz (Silica - SiO2)

Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.

As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.

Quartzite (Iron-stained)

Quartzite (primarily SiO2)

Chalcedony (Common Opal variant)

Silicon dioxide (SiO2) with varying levels of hydration

Moss Agate / Chalcedony

Silicon Dioxide (SiO2)

Carnelian (Chalcedony)

Silicon Dioxide (SiO2)

Banded Agate (Jasper-Agate)

Silicon Dioxide (SiO₂)

Thunderegg

Agate-filled Rhyolitic Nodule (SiO2)

Blue Lace Agate

Chalcedony (SiO2) with trace impurities

Chalcedony with Matrix

Silicon Dioxide (SiO2)

Carnelian (Orange Chalcedony)

Silicon dioxide (SiO2)

Carnelian

Carnelian (SiO2 - Silicon Dioxide with Hematite impurities)

Carnelian Agate

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) inclusions

Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Black Onyx

Chalcedony (Silicon Dioxide, SiO2)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Yellow Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Carnelian Agate

Carnelian (Silicon Dioxide: SiO2) with iron oxide impurities

Chalcedony (specifically Agate or Water-worn Quartzite)

Silicon Dioxide (SiO2)

Blue Lace Agate (Banded Chalcedony)

Silicon Dioxide (SiO₂)

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide impurities

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Carnelian Agate

Silicon dioxide (SiO2) - Chalcedony variety

Banded Agate

Agate (Silicon Dioxide, SiO2)

Aura Quartz

Titanium-coated Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz with Mica inclusion

Silicon Dioxide (SiO2) with Muscovite/Biotite inclusions

Clear Quartz

Silicon Dioxide (SiO2)

Quartzite

Quartzite (Primary mineral: SiO2)

Granodiorite (or Granite) Pebble

Phaneritic Felsic Igneous Pebble

Quartz with Tourmaline Inclusions (Tourmalinated Quartz)

SiO2 with complex borosilicate inclusions