← Back to Reference Database RI Chart SG Chart Fluorescence Hardness

Chrysocolla Chalcedony

Last updated: September 2026

Chrysocolla finely dispersed through chalcedony, traded as "gem silica". The properties here are chalcedony's, because the quartz host is what does the work: hardness 6.5–7, SG 2.58–2.64, RI 1.530–1.543. That is the whole reason it is a separate entry from chrysocolla the mineral (hardness 2–4, SG 1.93–2.40, RI 1.575–1.635) — one row cannot carry both, and the blended row used to take SG from the mineral and hardness from this material, a combination no stone can have. Colour is copper; everything a bench test measures is quartz.

Chrysocolla Chalcedony has a specific gravity of 2.61 and a refractive index of 1.530–1.543, with a Mohs hardness of 6.5–7.0. It is aggregate.

Physical & Optical Properties

RI Range1.530–1.543
SG Range2.58–2.64
SG Typical2.61
Hardness (Mohs)6.5–7
Crystal SystemTrigonal
Optic CharacterAggregate
Dispersion0.013
Fluorescence LWVariable
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsBlue Violet, Green
SpeciesQuartz
Blue VioletGreen

Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.

Through the refractometer

Chrysocolla Chalcedony varies 1.530 – 1.543 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 REFRACTIVE INDEX DORotate the stone through a full 360°, watching the boundary. SEEOne boundary that does not move as you rotate — and it isoften vague rather than crisp. Where it sits is not fixedfor this species: published at 1.530 – 1.543, and the stonedrawn here reads 1.536, between the dashed marks. MEANSThis is an aggregate — a mass of microscopic crystals — andon this instrument it looks exactly like a singly refractivestone. The refractometer cannot tell the two apart. Thepolariscope can: an aggregate stays light through a fullrotation, where a singly refractive stone stays dark. Computed from gems.json — edge positions are arithmetic, not drawn. RI increases upward; the field above the boundary is the dark one.

Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.

Through the polariscope

Chrysocolla Chalcedony Light throughout (AGG) 0° 45° 90° 135° ROTATION BETWEEN CROSSED POLARS Chrysocolla Chalcedony stays light in every position. Light crosses many randomly oriented grains, so some component always reaches the analyser. On a refractometer an aggregate is indistinguishable from a singly refractive stone; this is the test that separates them. Computed from optic character and transparency in gems.json. A polariscope separates singly refractive, doubly refractive and aggregate — it does not show the optic sign.

Drawn from the optic character and transparency above. A polariscope separates singly refractive, doubly refractive and aggregate; the optic sign needs a conoscope. How to take this reading.

Specific gravity, and what it rules out

Chrysocolla Chalcedony SG 2.58–2.64 WHERE IT SITS, AND WHAT ELSE IS THERE 1.0 2.0 3.0 4.0 5.0 SPECIFIC GRAVITY 30 other species in the table overlap this range, so a reading here narrows the field to 31 rather than naming the stone. This is the crowded part of the scale — the same careful measurement is worth far more higher up. Computed from the specific-gravity range in gems.json. Hydrostatic weighing — the bench method this site recommends; heavy liquids are toxic and regulated. Faint ticks are the other species in the table.

Drawn from the specific-gravity range above, against every other species in the table. How to take this reading.

Through the dichroscope

Chrysocolla Chalcedony One colour (no pleochroism) IDENTICAL AT EVERY ANGLE Chrysocolla Chalcedony shows no pleochroism, so both windows match at every orientation — turning the instrument changes nothing. That is a real negative result, and the reason it is worth knowing is below. Computed from pleochroism and pleochroic colours in gems.json. Window tints are derived mechanically from the colour words, not chosen; a neutral pair depicts no colour at all.

Drawn from the pleochroism above. Two windows that match mean either no pleochroism or the wrong angle — turn the instrument to tell. How the dichroscope compares.

AgateAmethystAmetrineAventurineBloodstoneCarnelianChalcedonyChrysopraseCitrineHawk's EyeOnyxPrasioliteRock CrystalRose QuartzSmoky QuartzTiger's Eye

Key Differentiators

Treatments

Measurement Guides

How to Identify a GemstoneHow to Measure Specific GravityHow to Use a RefractometerUV Fluorescence Testing

Identifying a chrysocolla chalcedony? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.

Try Loupewise Free →

Studying for the GIA, FGA, or FEEG practical? Chrysocolla Chalcedony is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.

Practice exams →