Chinese Onyx Lamps: How Light Transmission Works and What to Look For

Onyx is one of the most beautiful materials for lighting. When lit from behind, it glows like honey, with dramatic bands of color.

China produces stunning onyx lighting. Here's what you need to know about how light passes through it.

What Onyx Is

Onyx is a banded variety of chalcedony (a type of quartz). It forms in caves as layers build up over time.

Characteristics:

• Translucent to transparent

• Distinct bands (often parallel)

• Colors: white, honey, red, green, brown

• Softer than marble

• Takes a beautiful polish

How Light Transmits Through Onyx

Onyx is naturally translucent. Light passes through it, but not in a straight line — it scatters, creating a warm glow.

Factors affecting transmission:

Thickness:

• Thin (3-5mm): Transmits light well

• Medium (5-10mm): Good glow

• Thick (10mm+): Less light passes, moodier effect

Color:

• Light colors (white, honey): Transmit more

• Dark colors (red, brown): Transmit less

Banding:

• Bands may transmit differently

• Creates beautiful variation

Backlighting:

• Light source behind the stone

• Even lighting is better

• LED strips work well

Quality Factors

Good onyx:

• Even translucence (for its color)

• Clean, unbroken bands

• No cracks

• Consistent thickness where light passes

• Good polish

Poor onyx:

• Opaque spots

• Cracks that interrupt light

• Uneven thickness

• Dull finish

What to Look For in Photos

Lit photos:

• Look for even glow

• Bands should show clearly

• No dark spots

Unlit photos:

• Stone should look clean

• Bands distinct

• No visible cracks

Edge photos:

• Can you see thickness?

• Edges finished smoothly?

Price Ranges

Caring for Onyx

• Dust gently with soft cloth

• Clean with mild soap and water if needed

• Dry immediately

• Avoid acidic cleaners (can etch)

• Keep out of direct sun (colors can fade)

• Handle carefully (onyx is softer than marble)

Real vs. Fake

Some "onyx" is actually:

• Resin with printed pattern

• Glass

• Other stone dyed

How to tell:

• Real onyx is cold to touch

• Real has natural variations

• Bands continue through stone (not just surface)

• Real is heavy

Real Example: Good Quality

I bought an onyx pendant from a Chinese stone workshop. Price: $320.

What arrived:

• Beautiful honey color

• Even translucence when lit

• Distinct bands

• No cracks

• Glows like warm honey

Real Example: Poor Quality

A friend bought a cheap "onyx" lamp. Price: $90.

What arrived:

• Opaque spots

• Uneven thickness

• Some areas didn't glow at all

• Probably low-quality stone

The Bottom Line

Onyx lamps are stunning when done well. The way light passes through the stone is magical.

Look for even translucence, clean bands, and good thickness. Be willing to pay for quality.

A good onyx lamp will glow beautifully for generations.