search
  • Sign In
    Sign Up
  • English speaking customer support only

    1-800-464-1640

  • Change Language
  • USD
Boulder Opal Gemstones for Sale

Boulder Opal Store

We're proud to present our unique selection of natural Boulder Opal gemstones for sale. Boulder Opal has an earthy brown base-color mixed with the whole color spectrum of opal. This is the perfect gemstone for jewelry designers and hobby jewelers as well. We stock Boulder Opals in a large variety of shapes, sizes and price ranges. Use the filters on this page to quickly select the perfect fitting Boulder Opal for your jewelry needs. We ship our gemstones worldwide with a variety of shipping options.

Weight Size Clarity Price Origin
More
Single
Pairs
Lots
Faceted
Cabochons
Sort By:
Clear All
1 2 3 4 5 6 7 8

Boulder Opal

Opals really are a mixed bag of gemstones. Just some of the varieties include white opals, black opals, fire opals, pink Peruvian opals, hyalite opals and I could go on for quite a while yet.

Boulder Opals are one of the better known gemstones in this family. They are distinct from most other opals by still being connected to the rock in which they formed.

This means that the thin slivers of precious opal have a substantial foundation so it is much more durable and the dark rock is a perfect background for the vibrant play-of-color.

Boulder Opal Colors

There is no such thing as a typical Boulder Opal color. Every gemstone is different in both shape and color with every color of the rainbow a possibility. Not only can Boulder Opals feature all colors but as the stone moves other colors can flash or dance before your eyes.

The precious opal material that forms in cracks and crevices within the host rock is made up of tiny spheres in which light can bounce around creating the dazzling colors.

Larger spheres bring out the red colors while smaller spheres show up as blue. Large spheres are rarer so any Boulder Opal showing colors such as red or orange - the ones at the top of the rainbow - will be more expensive than the blues and greens found at the bottom.

Read more about gemstones colors here

Boulder Opal Species

Boulder Opals are just one of many types of opals found around the world. Some have the famous play-of-color while others are a single color but all are fascinating gemstones.

Just a few of the more well-known ones are:

And there are many more besides.

Boulder Opal Price

Like most gemstones, it is the color of the Boulder Opal that is the number one consideration when appraising its price. However, there are a couple of extra considerations to bear in mind with this stone.

There is the coverage - a gemstone that has a large area of precious opal spread over the surface will get a higher price than one with a few spots here and there.

A contrast between a dark background and a bright color can increase the value of the opal.

As we mentioned earlier, some colors are rarer than others and a simple rule is to work your way down the rainbow with the red at the top being the most expensive and the purple at the bottom being the least expensive.

This is a very basic rule which can vary from stone to stone with the coverage and contrast aspects to bear in mind.

Carat Weight

Boulder Opals are precious opal material still connected to the base rock so they tend to be quite large gemstones. They can also be irregular shapes to incorporate as much of the naturally occurring opal as possible.

Pricing Boulder Opals on carat weight can be a little tricky as there is often a lot of ironstone or sandstone left after cutting and polishing. It may be a very thick and heavy stone with just a thin veneer of colored opal on the front.

It is best to choose your Boulder Opal based on physical size - the length, width and height - rather than carat size. As a very rough guide, Boulder Opals can be anything from $2 to $15 per carat for basic colors up to $50 to $800 per carat for gemstones with outstanding colors, depending on color, coverage and contrast.

Treatments

Generally, Boulder Opals are a completely natural gemstone with no treatment other than cutting and polishing.

As we have said, the contrast between the opal and the rock background can increase the value so there have been cases of the base rock being smoked or soaked in sugar to darken up the body but this is not very common in Boulder Opals and happens more with Black Opals.

Sometimes the precious opal can come loose from the rock backing and can be reattached with glue or resin. This would be difficult to spot unless a sudden impact or high heat breaks the seal but we are not aware of this being a serious problem.

Any treatment received by any of our gemstones is clearly disclosed.

Where are Boulder Opals found?

Basically all Boulder Opals come from central Queensland. This may not sound that impressive but it is an area about the size of California and home to about 200,000 people (and lots of kangaroos, rock wallabies, goannas and spiders).

What jewelry is Boulder Opal suitable for?

Boulder Opals have a rating of 5.5 to 6.5 on Mohs hardness scale. This would usually make them a little bit fragile for many jewelry items and not suitable for daily wear, however Boulder Opals are still attached to the durable rocks they formed in so are much tougher than the rating would suggest.

Large and striking Boulder Opals cut into interesting odd shapes can help create wonderful and unique jewelry items, especially pendants, brooches and earrings where durability is not such an issue. Boulder opal rings in protective settings can be particularly striking items of jewelry.

Birthstones and Anniversaries

Boulder Opals are the birthstone of October and would make an ideal gift for anyone celebrating a birthday in that month.

A Boulder Opal is the traditional gemstone gift for the 14th wedding anniversary.

Over 18 Years in the Gemstone Business!

Thank you for trusting us with your purchase!

Overall Rating -> 10 star ratings

No issues at all. It was great.

Posted By LJXK in May, 2023
Source: Bizrate

Overall Rating -> 9 star ratings

Everything was good but since I am still new I was surprised at how small the stones where.

Posted By Js in May, 2023
Source: Bizrate

Overall Rating -> 10 star ratings

Excellent experience!

Posted By Steph in April, 2023
Source: Bizrate
STAY IN TOUCH
*You're signing up to receive GemSelect promotional email.
Partners and Trust Payment options

Switch to Mobile Version

Privacy Notice © 2005-2023 GemSelect.com all rights reserved.

Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.

1088

More Shapes
  • Asscher Cut
  • Baguette / Scissor Cut
  • Baguette Cabochon
  • Baguette Checkerboard
  • Baguette Crystal Cluster
  • Baguette Facet
  • Baguette Rose-Cut
  • Baguette Step Cut
  • Baguette Sugarloaf Cabochon
  • Ball
  • Baroque
  • Barrel
  • Barrel / Checkerboard
  • Barrel / Full-Round
  • Barrel Cabochon
  • Barrel Rose Cut
  • Bear Carving with Hole
  • Bird Carving
  • Briolette
  • Briolette with Hole
  • Bullet Shape Checkerboard
  • Carved Baguette
  • Carved Bird
  • Carved Cameo
  • Carved Cushion
  • Carved Elephant
  • Carved Fancy
  • Carved Fish
  • Carved Fish with Hole
  • Carved Flower
  • Carved Frog
  • Carved Fruit
  • Carved Half Heart
  • Carved Heart
  • Carved Heart Cabochon
  • Carved Leaf
  • Carved Marquise
  • Carved Marquise Cabochon
  • Carved Octagon
  • Carved Oval
  • Carved Oval Cabochon
  • Carved Pear
  • Carved Pear Cabochon
  • Carved Rhomb
  • Carved Rose
  • Carved Rose with Half Drilled Hole
  • Carved Round
  • Carved Round Bar
  • Carved Round Cabochon
  • Carved Shell
  • Carved Square
  • Carved Teardrop
  • Carved Trillion
  • Carved Turtle
  • Cushion Buff-Top
  • Cushion Cabochon
  • Cushion Checkerboard
  • Cushion Checkerboard (double sided)
  • Cushion Checkerboard (double sided) with Hole
  • Cushion Concave Cut
  • Cushion Concave Fantasy Cut
  • Cushion Crystal Cluster
  • Cushion Mixed Cut
  • Cushion Rose-Cut
  • Cushion-Cut
  • Diamond-Cut
  • Drilled Faceted Sphere
  • Drilled Sphere
  • Drilled Square Rondelle
  • Drilled Square Rondelle Slice
  • Fancy Cabochon
  • Fancy Carved Cushion
  • Fancy Carved Oval
  • Fancy Carved Pear
  • Fancy Carved Trillion
  • Fancy Carving
  • Fancy Crystal Cluster
  • Fancy Cut
  • Fancy Facet
  • Fancy Fantasy Carving
  • Fancy-Cut
  • Fantasy Carved Flower
  • Fantasy Carved Flower Cut
  • Fantasy Carved Leaf
  • Flower Carving
  • Flower-Cut
  • Half Cylinder Cabochon
  • Half Heart Cabochon
  • Half Heart Facet
  • Half Moon Cabochon
  • Half Moon Facet-Cut
  • Half Moon Faceted
  • Half-Drilled Briolette
  • Half-Drilled Heart Cabochon
  • Half-Drilled Heart Checkerboard Facet
  • Half-Drilled Heart Checkerboard (double sided
  • Half-Drilled Sphere
  • Heart Buff-Top
  • Heart Cabochon
  • Heart Checkerboard
  • Heart Checkerboard (double sided)
  • Heart Concave Cut
  • Heart Crystal Cluster
  • Heart Facet
  • Heart Rose-Cut
  • Hexagon Crystal Cluster
  • Hexagon Cut
  • Marquise Buff-Top
  • Marquise Cabochon
  • Marquise Checkerboard
  • Marquise Checkerboard (double sided)
  • Marquise Concave Cut
  • Marquise Crystal Cluster
  • Marquise Facet
  • Marquise Mixed Cut
  • Marquise Rose-Cut
  • Marquise Slice
  • Marquise Sugarloaf Cabochon
  • Octagon / Scissor Cut
  • Octagon Buff-Top
  • Octagon Cabochon
  • Octagon Checkerboard
  • Octagon Concave Cut
  • Octagon Facet
  • Octagon Mixed-Cut
  • Octagon Step Cut
  • Oval Bar Cut
  • Oval Buff-Top
  • Oval Cabochon
  • Oval Cabochon with Hole
  • Oval Carved Cameo
  • Oval Checkerboard
  • Oval Checkerboard (double sided)
  • Oval Concave Cut
  • Oval Crystal Cluster
  • Oval Diamond-Cut
  • Oval Facet
  • Oval Fancy Facet
  • Oval Mixed Cut
  • Oval Portuguese-Cut
  • Oval Rose-Cut
  • Oval Rose-Cut (double sided)
  • Oval Slice
  • Pear Cabochon
  • Pear Checkerboard
  • Pear Checkerboard with Hole
  • Pear Concave Cut
  • Pear Crystal Cluster
  • Pear Double-Sided Checkerboard
  • Pear Facet
  • Pear Rose-Cut
  • Pear Shape Sugarloaf Cabochon
  • Pencil
  • Pencil Cut
  • Princess-Cut
  • Pyramid Cabochon
  • Rhomb Cabochon
  • Rhomb Checkerboard
  • Rhomb Checkerboard (Double-Sided)
  • Rhomb Crystal Cluster
  • Rhomb Facet
  • Rondelle
  • Round Buff-Top
  • Round Cabochon
  • Round Carved Cameo
  • Round Checkerboard
  • Round Checkerboard (double sided)
  • Round Concave Cut
  • Round Crystal Cluster
  • Round Drilled Checkerboard (Double Sided)
  • Round Drilled Rondelle
  • Round Facet
  • Round Mixed-Cut
  • Round Petal Cut
  • Round Rose-Cut
  • Round Rose-Cut (double sided)
  • Shark Fin Cabochon
  • Shield Cabochon
  • Sliced Crystal
  • Spherical
  • Square / Scissor Cut
  • Square Buff-Top
  • Square Cabochon
  • Square Checkerboard
  • Square Crystal Cluster
  • Square Facet
  • Square Mixed-Cut
  • Square Step-Cut
  • Square Sugarloaf Cabochon
  • Square with Hole
  • Star Facet
  • Tapered Baguette Cabochon
  • Teardrop Cabochon
  • Trapezoid
  • Trapezoid Cabochon
  • Triangle
  • Triangle Facet
  • Trillion Buff Top
  • Trillion Cabochon
  • Trillion Checkerboard
  • Trillion Concave Cut
  • Trillion Crystal Cluster
  • Trillion Facet
  • Trillion Rose-Cut
  • Trillion Shape Sugarloaf Cabochon
  • Undrilled Briolette Teardrop
Popular Gemstones
  • Sapphire
  • Emerald
  • Ruby
  • Aquamarine
  • Zircon
  • Opal
  • Topaz
  • Tourmaline
  • Garnet
  • Amethyst
  • Citrine
  • Tanzanite
All Gemstones (145)
A B C D E F G H I J K L M N O P Q R S T V Z
  • Actinolite Cat's Eye
  • Agate
  • Agate Geode
  • Almandine Garnet
  • Amazonite
  • Amethyst
  • Amethyst Geode Slice
  • Ametrine
  • Ammolite
  • Andalusite
  • Andesine Labradorite
  • Apatite
  • Aquamarine
  • Aventurine
  • Azotic Topaz
  • Azurite
  • Black Opal
  • Bloodstone
  • Boulder Opal
  • Carnelian
  • Cat's Eye Apatite
  • Cat's Eye Aquamarine
  • Cat's Eye Gemstones
  • Cat's Eye Moonstone
  • Cat's Eye Opal
  • Cat's Eye Scapolite
  • Chalcedony
  • Charoite
  • Chocolate Opal
  • Chrome Diopside
  • Chrysoberyl
  • Chrysoberyl Cat's Eye
  • Chrysocolla
  • Chrysoprase
  • Citrine
  • Color Change Gemstones
  • Color-Change Diaspore
  • Color-Change Fluorite
  • Color-Change Garnet
  • Coral
  • Demantoid Garnet
  • Dendritic Agate
  • Diamond
  • Druzy Amethyst
  • Druzy Azurite
  • Druzy Citrine
  • Druzy Variscite
  • Emerald
  • Enstatite
  • Fire Agate
  • Fire Opal
  • Fluorite
  • Fossil Coral
  • Garnet
  • Golden Beryl
  • Grandidierite
  • Grossularite Garnet
  • Hawk's Eye
  • Hematite
  • Hemimorphite
  • Hemimorphite Druzy
  • Hessonite Garnet
  • Howlite
  • Idocrase
  • Imperial Topaz
  • Iolite
  • Jade Gemstones
  • Jadeite
  • Jasper
  • Kornerupine
  • Kunzite
  • Kyanite
  • Labradorite
  • Lapis Lazuli
  • Larimar
  • Malachite
  • Malaya Garnet
  • Mali Garnet
  • Maw-Sit-Sit
  • Moonstone
  • Morganite
  • Mother Of Pearl
  • Mystic Quartz
  • Mystic Topaz
  • Nuummite
  • Obsidian
  • Onyx
  • Opal
  • Opal Doublet
  • Opal In Matrix
  • Pearl
  • Peridot
  • Pietersite
  • Prehnite
  • Pyrite
  • Pyrope Garnet
  • Quartz
  • Quartz Cat's Eye
  • Quartz With Hedenbergite
  • Quartz With Marcasite
  • Rainbow Moonstone
  • Rainbow Pyrite
  • Rhodochrosite
  • Rhodolite Garnet
  • Rhodonite
  • Rose Quartz
  • Rubellite Tourmaline
  • Ruby
  • Ruby In Fuchsite
  • Ruby-Zoisite
  • Rutile Quartz
  • Sapphire
  • Scapolite
  • Scolecite
  • Seraphinite
  • Serpentine
  • Sillimanite
  • Sillimanite Cat's Eye
  • Smithsonite
  • Smoky Quartz
  • Snowflake Obsidian
  • Sodalite
  • Spectrolite
  • Spessartite Garnet
  • Sphalerite
  • Sphene
  • Spinel
  • Star Diopside
  • Star Garnet
  • Star Gemstones
  • Star Moonstone
  • Star Rose Quartz
  • Star Ruby
  • Star Sapphire
  • Strawberry Quartz
  • Sunstone
  • Tanzanite
  • Tiger's Eye
  • Tiger's Eye Matrix
  • Topaz
  • Tourmaline
  • Tsavorite Garnet
  • Turquoise
  • Variscite
  • Zircon
Main Categories
  • New Arrivals
  • Gemstone Lots
  • Calibrated Gemstones
  • Gemstones By Piece
  • Top Grade Gems
  • Matching Pairs
  • Cabochon Gemstones
  • Drilled Gems, Briolettes and Beads
  • Birthstones
  • Gemstone Carvings
  • Fancy Gemstones
  • Star Gemstones
  • Unheated Sapphire
English speaking customer support only

Toll Free - USA & Canada only:
1-800-464-1640

International:
+66-39609697

Save Money
No shipping Fees for Additional Items!
$8.90 Worldwide Shipping

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
Size and Weight

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart