Types of Opal Gemstones
Australian Boulder Opals
Second only to black opal in value, second to none in beauty. The boulder opal is mined from are ironstone boulders found in Australia. These make excellent gemstones for custom pieces, in addition to jewelry, you can find sculptures made out of the ore that contains these opals.
Of all the opals to work with, I think these are my favorite. They typically come as a free-form slab cut. A Freeform shape, referring to the silhouette, or footprint of the stone, are generally kind of gently rounded natural shapes, like a kidney bean smaller on one end than the other, or leaf shapes, sometimes slightly more dramatic dagger-like shapes, that kind of thing. The stone cutters look at the material that they have available and give it whatever shape seems best given the way the color presents. Occasionally these stones will be more of a cabochon cut, which is to say have a slightly domed surface rather than flat like the slabs.
These are also quite beautiful, the organic shapes of the free forms, weather slab or cabochon, really lend themselves well to the kind of natural asymmetrical designs which I consider to be my forte. For this reason, as well as the endless variety and beauty of the stone, opals are one of my all-time favorite stones to work with!
Koroit Boulder Opal
This is another type of boulder opal hailing from Queensland. These opals are often very large, with unusual patterns. If you are looking for Exquisite Natural Opals, this is where I would start! In general Australian opals are truly stunning!
The distinguishing characteristic of these opals is that they have an unusually large amount of matrix or the mother stone in which the opal is formed. The matrix is typically chocolate or caramel-colored brown, shot through with strange patterns of electric blues and greens. The contrast between the two is striking. In my opinion, stones like these are well suited for designs that feature relatively simple metalwork, because the stone itself is such a spectacle!
Australian Black Opal
The rarest opal, the black opal, is also the most sought after type. Another stunning Australian opal mined in the fields of Lightning Ridge, which is the Black Opal Capital of the World. The remarkable darkness is caused by carbon and iron oxide trace elements. This darkness makes the rainbow colors of the opal pop!
These towns always remind me of something utterly mystical, like ancient spirits circling the depths of a wizard's crystal ball. Because of the composition of the stones, there's a certain depth to the jelly matrix that draws the eye down deep into the gem, and maneuvering the stone one way and the other causes these dramatic flashes of color to come rolling to the surface. For me, there's something genuinely primeval about these stones, an almost unnerving depth.
Also known as the Yowah nut opal is a small boulder that looks like you guessed it a nut that fell from a tree. This is another Australian opal. The locals would sometime claim to be nut mining. Due to their shape and size, these opals have never been used in mass production or jewelry and are instead used in handcraft pieces.
Originating as small somewhat spherical like shapes, these opals have a kind of layered quality that can appear as concentric circles when they're cut in specific ways, often with the matrix on the outside, contrasting with brightly colored opalized interiors. One of nature's little spectacles, there are a bizarre yet captivating combination of the humble solid matrix stone, surrounding and ephemeral, and turbulent dream-like interior. Beautiful stones that inspire the imagination and lend themselves to dramatic design possibilities.
Tanzanian Green Opal
East African opals are often bright green or sometimes honey-colored. It is not unusual for them some time to have a sparkle when moved in bright light. The <a href="https://www.gia.edu/doc/Chrysoprase-and-Prase-Opal-from-Haneti-Central-Tanzania.pdf"> green prase opal </a> is another wide used variety of opal.
A rare stone for those who consider themselves collectors. It's like a combination of imperial Jade, and Colombian emerald in terms of its opacity and translucence. These are almost always cut into cabochon shapes, sometimes calibrated and sometimes freeform. They will often have flecks of matrix or other minerals embedded in them, giving them a somewhat organic quality. These are gorgeous stones. Again, I like the more unusual shapes and will sometimes integrate them with other materials. For example, a green oval pendant on a strand of black tourmaline natural crystals to highlight the black inclusions of the green stone. These kinds of combinations can be very striking!
To sum it up in one word, Wow. The legend, Brazilian opals are like nothing else on earth. All these opals are hand mined in the remote North-East Region of Brazil. If you are looking for a small opal pendant, I would certainly look at these stones.
These stones are characterized by a jelly matrix that tends towards shades of off-white, sometimes honey colors, with bright flex of pink purple green and yellow suspended in them. Almost always cut in cabochon shapes. These opals tend to be more affordable than their Australian counterparts, so worth considering if you're thinking about a more substantial piece and budget is an issue.
Mexican Fire Opal
Forged in the depths of Mordor, ok not really, but these opals have remarkable deep reds, oranges with specks of blue. The Mayans and Aztecs used this stone extensively in their mosaics and rituals—these stones with the most vibrant oranges and reds originate from Mexico.
Because the better quality stones tend to have good translucence, these are faceted more often than any of the other opal varieties, although they're also available as cabochons. One of only a handful of naturally colored orange gemstones in the world, these stones boast the strongest color saturation of all the opals. If orange is your color, the Mexican fire opal is definitely for you. The intensity of this orange looks great in designs that also use gold, possibly oxidized sterling or other black material. These stones are all about drama, drama, drama! We would love using these stone in engagement rings and other custom rings
Hailing from the Andes mountains, this is the national stone of Peru. These opals are really two different types of opals, the blue which sparkles win hit with sunlight and the pink opal. Teach gym stones are rarely used in custom made jewelry, and we don't understand why because they make magnificent pieces.
The charm of this beautiful stone is in its understated elegance. My favorite of these is the more aqua colored varieties, particularly the ones that have undulating striations to them. If well-cut, they offer a soothing landing place for the eye, tranquil like a high mountain lake.
Golden hues of honey and Amber, these opals are rarely used in the trade, mined in Slanské hills in eastern Slovakia. The famous Trojan Fire opal given to empress Giuseppina from Napoleon was a Slovakian opal.
These apples are reminiscent of Baltic Amber in their color tones and banded composition. Although some can have flecks of more intense color buried in its depths, most rely on subdued and earthy glow for their beauty. These stones naturally lend themselves towards organic designs, sometimes featuring other unusual materials like rusted metal or fossilized wood.
Kalimaya Black Opal
Hand mind by small operations in Indonesia, these are very rare. You have to be careful because he's her often list it and not true Kalimaya black opal's instead, they are treated Ethiopian opals. These are referred to by some in Indonesia as Kalimaya stones or Riverstone. Finding a true Kalimaya is very difficult but well worth the effort. Also, know as the Batu Opal.
Design-wise and aesthetically, the same rules apply to this stunning stone as to the Australian black opal. It's essentially the same material, although some of the fossilized varieties can be quite distinctive and unique. This stone is by no means inexpensive, and fakes are everywhere so you'll want a certification to go with your stone. If you can find them, they are of exceptionally high quality and lend themselves to beautiful and mystical design opportunities!
Actually, several different types of Ethiopian opals exist, but for our purposes, they all make great stones for custom pieces. Just understand that most Ethiopian Black Opals are treated. We often look for a stone with honeycomb patterns as it produces some of the best colors and glimmers. The Welo Patchwork Harlequin Pattern is the rarest and most sought after of the honeycomb patterns.
These are still relatively new arrivals on the gemstones scene. They will most often have a honey colored matrix, usually packed with an absolute firestorm of colored flecks suspended within them. Most commonly found in calibrated cuts, and typically as cabochons (Though occasionally faceted). To me, these have many of the same design opportunities as the Indonesian and Australian varieties, often at a more affordable price. The honey-colored matrix adds a measure of warmth that can occasionally make for some unusual combinations with unlikely bedfellows like Amber, Carnelian or other choices
Often referred to as the queens' opal as Queen Elizabeth II has a 200-carat Andamooka pendant. This opal, when untreated, can appear milky or white. This is the only type of opal know to sometimes contain dinosaur bones. These stones are often treated to produce darker blacks; these are known as the Andamooka matrix.
These are always cut into cabochons, typically both reform and calibrated cuts. The range and quality can be quite wide, but a good quality stone can show an exceptionally good color with a winning combination of the brilliance of the boulder opal, with the depth of the black opal.