Chalcedony

Agate

Agate is chalcedony that grew in bands. Blue lace agate shows pale blue bands; banded agate warmer browns and oranges. It is cut as cabochons, beads and cameos.

  • Blue lace agateBlue lace agate
  • Banded agateBanded agate

At a glance

Mineral
Banded chalcedony (fine-grained quartz)
Refractive index
1.544
Dispersion (C–F)
—
Specific gravity
2.65
Mohs hardness
6.5–7
Wear
Durable for most jewellery.

Agate in Jart

The 2 looks in the studio's material library, with the values the renderer uses.

Optics of Agate in Jart
StoneColourRIDispersion C–FAbbeSGColour depth
Blue lace agate#8fa3b81.544——2.65opaque
Banded agate#b06a3a1.544——2.65opaque

RI refractive index (nd). Dispersion C–F nF − nC, the spread between blue and red light; many gem tables quote the B–G figure instead (diamond 0.044, here 0.025). Abbe number: lower means more fire. SG specific gravity, used for carat estimates in Design Facts. Colour depth the path through the stone after which white light takes the stone's full colour; shorter paths look paler.

How it renders

With a refractive index of 1.544, a polished agate facet reflects 4.6% of light that meets it face-on (diamond: 17.2%). Light inside the stone that meets a facet more than 40.4° from straight on cannot leave and is reflected back in; the smaller that angle, the more light a good cut returns to the eye (diamond 24.4°, quartz 40.4°).

It is opaque: light reflects from its surface and does not travel through it, so it shows no fire, and its look comes from its colour, its polish and what the lighting reflects.

Jart renders agate as an opaque, polished stone: light reflects from its surface instead of entering it, so its colour reads evenly and its gloss comes from the lighting.

All gemstones · Metals · Stone and metal pairings · Finishes

Render agate on your own design.

Open a 3DM, STL or GLB file, or a sample ring, choose the stone and the metal, and render it photoreal in your browser. No account needed.

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