Micro round rainbow moonstone cabochons, 5 mm in diameter, with flat backs. Blue adularescence flash visible under spot light. Available in lots of 2 or 10 pieces — the 5 mm format is the most versatile in the micro range: large enough for a solitaire stud earring and small enough for pavé and accents. Selected from a wholesale lapidary market.
Item Details
| Mineral |
Rainbow Moonstone (oligoclase, sodium-calcium feldspar; commercially “rainbow moonstone”) |
| Dimensions |
Approximately 5 mm in diameter. Variation of ±0.5 mm due to being hand-cut. |
| Shape and Back |
Round, flat back |
| Finish |
Mirror polished |
| Hardness |
6–6.5 Mohs — we recommend a closed bezel setting for daily wear |
| Origin |
India (Rajasthan) |
| Treatment |
Untreated. The blue flash is natural (adularescence) |
| Item Type |
Available in lots of 2 pieces (pair) or 10 pieces |
This Specific Piece
At 5 mm, rainbow moonstone offers a more pronounced adularescence flash than the 4 mm due to the larger surface area that intercepts light. A 1 mm difference may seem insignificant, but in terms of capture area, it represents 56% more surface than the 4 mm round, resulting in a wider and more visible light band.
How Adularescence is Formed
See the full explanation in the 4 mm round cabochon listing (layers of oligoclase/adularia with internal light interference). Of note for the 5 mm: this size allows the jeweler to orient the stone more easily to center the point of maximum adularescence before setting, a technical advantage over 2–3 mm formats.
What Mountings it Works For
-
Solitaire stud earrings (925 silver) — the 5 mm round is the standard size for a discreet but visible stud. In silver with a bright finish, the contrast between the metal and the blue adularescence is elegant.
-
Pavé of round cabochons — combined with the 4 mm round and the 7×5 mm oval (available in the same catalog), it allows for creating pavé with natural variation.
-
Accent rings — flanking a larger central stone (opal, tourmaline), the 5 mm adds peripheral light without competing.
-
Floral or branched wire wrap — the 5 mm round is a common choice in wire wrap as a central "pearl" in floral motifs.
Moonstone in History
In ancient Rome, moonstone was the traveler's gem: Pliny the Elder recommended it as a protective amulet on journeys.
In crystal tradition, rainbow moonstone (intuition, cycles, and sensitivity) is especially valued in jewelry for its ability to visually change with ambient light.
The symbolic properties attributed to minerals belong to cultural and historical traditions. They are shared for educational purposes, not as medical advice or a substitute for professional care.
How to Recognize Genuine Rainbow Moonstone
See authenticity criteria in the 4 mm round listing. At 5 mm, the difference between genuine moonstone and white glass is more noticeable: authentic adularescence has visual depth — light seems to float beneath the surface, not on top of it as in enamels or coatings.
Frequently Asked Questions
Does the 2-piece lot come as a calibrated pair?
The 2 pieces come from the same block of material and are selected to be as similar as possible in tone and flash, but being hand-cut, they have a variation of ±0.5 mm and minor differences in flash intensity. For exact pair earrings, the jeweler can orient the two cabochons so that the differences are minimized.
Is the 5 mm brighter than the 4 mm?
The adularescence is not "brighter" because the stone is larger, but the luminous band is wider and more visible at a greater distance. The intensity of the flash depends on the quality of the material (number and fineness of feldspar layers), not the size.
Are they suitable for daily wear rings?
With a closed bezel in 925 silver, yes. Without a protective setting (open prong), we recommend occasional use given the cleavage of feldspar.
See also: all our cabochons · silver earrings · mineral blog.
