What is Sard?


Sard is a variety of chalcedony that is often found in India, Brazil, and Uruguay. It’s primarily used as a gemstone and is popular for its brown to reddish-brown color.

Sard is a unique gemstone that comes in shades of brown to reddish-brown. Its earthy hue and unique appearance make it a popular choice for jewelry and decorative items, especially beads and pendants.

Gemstone Properties

Chemical ClassificationInorganic - Silicate (Chalcedony)
ColorReddish-brown, varying from deep brown to more translucent reddish hues.
LusterWaxy to vitreous.
OccurrenceIndia, Brazil, and Uruguay.
FormationTypically found in hydrothermal veins and in nodules in volcanic rocks.
DiaphaneityTranslucent to opaque
CleavagePerfect in one direction
Mohs Hardness6.5 to 7
Specific Gravity2.58 - 2.64
Diagnostic PropertiesBrownish-red chalcedony.
Chemical CompositionSiO2
PleochroismNot observed in sard.
Crystal SystemHexagonal (variety of Quartz)
Optical PropertiesUniaxial (+)
Refractive Index1.530 - 1.539
2V angleNot applicable (isometric)
DispersionNot typically noted for its dispersion.