Sard

Sard is a variety of chalcedony that is in fact microcrystalline quartz. It is a brownish red variety that is similar to agate in appearance.

Sard stone may be imitated by saturating chalcedony with an iron solution. It is common for the rough of the stone to have pitted, partly worn surface.

Sard pebbles are also found as dark, semi-translucent stones with waterworn surface.

Occurrence

Sard is found in many countries around the world. It is formed by deposition of silica in gas cavities in lava. That gives the stone is characteristic band.

Sard Properties

• Specific Gravity: 2.61
• Refractive Index: 1.53-1.54
• Birefringence (DR): 0.004
• Luster: Vitreous
• Crystal Structure: Trigonal
• Composition: Silicon dioxide
• Hardness: 7

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Crystals Directory

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Birthstone

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