Opal Types: The Complete Guide to Different Kinds of Opal

Opal is often called the “gem of a thousand colors”—and for good reason. Each stone is like its own universe, with shifting flashes of rainbow light that make no two opals exactly the same. Many people love to showcase these mesmerizing gems in opal rings, pendants, or earrings. But with such variety, many people find themselves asking: What are the different types of opal, and how do I tell them apart?

This complete guide to opal types will walk you through the main varieties of opal, how they’re classified, what determines their value, and how to care for them. By the end, you’ll know which opal best suits your taste, budget, or jewelry style.

Table of Contents

• Overview of Opal Types
• Main Precious Opal Types
• Common Opal Types (Non-Precious Opal)
• Natural Opal vs. Lab & Composite Opal
• What Determines Opal Value
• Care & How to Identify Real Opal
• Opal Types FAQs
  

Overview of Opal Types

When jewelers or gemologists classify different types of opal, they usually consider these factors:

• Play-of-color → Does the stone show opal’s famous rainbow flashes? (Yes = precious opal, No = common opal).
• Body tone → The background color, ranging from deep black (N1)  to milky white (N9). 
• Transparency → Is it opaque, translucent, or crystal-clear?
• Formation → Solid opal, boulder opal in host rock, or opal filling natural pores (matrix).
• Origin & treatment → Natural solid, composite (doublet/triplet), or lab-grown.

Together, these dimensions create the diverse family of opal varieties.

Opal Classification System Overview

Category	Type	Key Features	Value Relevance
Play-of-Color	Precious Opal	Displays play-of-color, internal spectral flashes	Main factor in value
	Common Opal	No play-of-color, only body color	Lower value
Body Tone	Black Opal	Body tone N1–N4, darkest background	Highest value
	Dark Opal	N5–N6, medium dark	High value
	Light/White Opal	N7–N9, white to pale	Affordable, widely available
	Fire Opal	Transparent to translucent, red/orange/yellow body color, sometimes play-of-color	Valued for vivid color
Transparency	Crystal Opal	Transparent to semi-transparent, vivid play-of-color	Very valuable
	Water Opal	Colorless, transparent to semi-transparent, sometimes faint play-of-color	Rare, delicate beauty
Origin & Structure	Natural Opal	Mined directly, one solid piece	Standard reference
	Composite Opal	Assembled opal (e.g., doublets, triplets), layered structure	Lower durability & value
	Lab Opal	Lab-created, with physical/optical properties similar to natural opal	Affordable alternative

Main Precious Opal Types

Precious opal is what most people think of when they imagine opals—stones with mesmerizing flashes of color. The following are the main types of natural precious opals, along with their characteristics and sources.

Type	Appearance	Famous Sources
Black Opal	Dark body tone (N1–N3) with vibrant, dramatic play-of-color. The rarest and most valuable opal.	Lightning Ridge, Australia
White / Light Opal	Pale to milky body tone, with soft pastel-like flashes.	Coober Pedy, Australia; Ethiopia
Crystal Opal	Transparent to translucent, with color play that seems suspended inside the stone.	Australia, Ethiopia, Mexico
Boulder Opal	Thin opal veins naturally within ironstone, creating striking contrast.	Queensland, Australia
Fire Opal	Vivid orange to red body color, sometimes with play-of-color. Even without flashes, its fiery hue is striking.	Mexico, Ethiopia

✨ Rare types also include Matrix Opal, Moss Opal, and Dendritic Opal, which look like tiny landscapes inside the gem.

Common Opal Types (Non-Precious Opal)

Common opal (also called potch) doesn’t display play-of-color, but it can still be enchanting. These opals typically display a milky-white, translucent to opaque appearance, with a soft, milky sheen known in gemology as opalescence. Popular varieties include:

• Colored Common Opal – Pink, blue, green, lavender, or other natural hues.
  
• Moss / Dendritic Opal – Opals with tree-like or mossy inclusions.
  
• Opalized Wood & Fossils – Ancient organic matter replaced by opal, preserving natural textures.
  
• Hyalite (Opal-AN) – A glassy, clear opal that may glow under UV light.
  

Natural Opal vs. Lab & Composite Opal

Based on how they are formed, opals can be divided into two main categories: natural opals (formed entirely by nature) and lab-grown or composite opals.

Natural Opal

Natural opals form over millions of years as silica-rich water deposits harden into shimmering gemstones. They are cut and polished, but not otherwise altered. Three main categories exist:

• Solid Opal (Type 1) – One entire piece of opal, such as black, white, or crystal opal.
  
• Boulder Opal (Type 2) – Opal layers that naturally sit on ironstone host rock.
  
• Matrix Opal (Type 3) – Opal that fills pores and veins in host rock, creating speckled or web-like patterns.
  

Lab & Composite Opal

These are man-made or assembled stones that mimic or enhance natural opal. They are beautiful and affordable, but carry different value.

• Doublet Opal – A thin slice of opal glued onto a dark backing to boost contrast.
  
• Triplet Opal – Like a doublet, but with an added protective clear cap.
  
• Lab Opal – Lab-grown opals that may look convincing but often show a very regular “snake-skin” pattern.

💡 Are they worth buying? Yes—if you’re on a budget or want everyday wear. Just note that they differ in durability and value retention compared to natural solid opals.

What Determines Opal Value

Not all opals are priced equally. Jewelers evaluate opals based on:

1. Play-of-color → Bright, diverse, and evenly spread flashes rank highest. (Color value: red > orange > green > blue).
2. Body tone → Darker = stronger contrast and usually higher value.
3. Transparency → Crystal-clear or translucent stones are prized.
4. Pattern → Rare patterns like harlequin, mosaic, or rolling flash fetch premium prices.
5. Brightness Scale (1–5) → Higher brightness means higher value.
6. Origin → Lightning Ridge black opals, Ethiopian crystal opals, and Mexican fire opals are especially prized.
7. Size & cut → Larger cabochons with good polish hold more value.
8. Treatment → Natural solids > doublets/triplets > synthetics.

Care & How to Identify Real Opal

Opal Care Tips

• Mohs hardness: 5.5–6.5 → softer than diamonds. Handle with care.
• Avoid: ultrasonic cleaners, extreme heat, sudden temperature change, harsh chemicals.
• Clean gently with a damp cloth. Store separately.
• Don’t soak doublets/triplets (water may weaken glue).

👉 See our Opal Jewelry Care Guide for more details.

Identifying real vs. lab/composite opal:

• Lab opals often show a highly regular, “snake-skin” pattern.
• Doublets and triplets have visible layering when viewed from the side.
• A clear glassy dome usually means a triplet.

For valuable stones, request a gemological certificate that specifies body tone, transparency, and whether it’s natural or treated.

Opal Types FAQs

Final Thoughts

From the mysterious depths of black opal to the fiery glow of Mexican fire opal, each opal type has its own magic. Whether you’re drawn to dramatic flashes or soft, pastel hues, there’s an opal variety that can perfectly reflect your personality.

✨ At MollyJewelryUS, we offer a wide variety of opal jewelry designs, from rings to pendant necklaces. We also provide custom services, so you can even create the opal engagement ring of your dreams.