SHOP 160,000+ BUY IT NOW GEMS
OR TRY OUR AUCTIONS WITH NO BUYERS FEES
100% NATURAL GEMS & VERIFIED SELLERS
Gemma AI

You have not bid on this auction.

Current Bid
1
Bids
Closed
11/04/2025 12:32 am

4.75-CTS DUMORTIERITE ROUGH SPECIMEN RARE MINERAL RG-4215 RAREGEMS

1 bid
1436 views
5 watching
Details
SKU
RG-4215
Dimensions (mm)
14.8 x 6.5 x 6.2mm
Weight (cts)
4.75
Treatment
No Treatment
Type
Specimen
Colours
Description

DUMORTIERITE

NICE PALE  BLUE COLOUR

FINE CRYSTAL SPECIMEN


Dumortierite is a fibrous variably coloured aluminium boro-silicate mineral, Al7BO3(SiO4)3O3. Dumortierite crystallizes in the orthorhombic system typically forming fibrous aggregates of slender prismatic crystals. The crystals are vitreous and vary in color from brown, blue, and green to more rare violet and pink. Substitution of iron and other tri-valent elements for aluminium result in the color variations. It has a Mohs hardness of 7 and a specific gravity of 3.3 to 3.4. Crystals show pleochroism from red to blue to violet. Dumortierite quartz is blue colored quartzcontaining abundant dumortierite inclusions.

Dumortierite was first described in 1881 for an occurrence in Chaponost, in the Rhône-Alps of France and named for the French paleontologist Eugène Dumortier (1803–1873).[4] It typically occurs in high temperature aluminium rich regional metamorphic rocks, those resulting from contact metamorphism and also in boron rich pegmatites. The most extensive investigation on dumortierite was done on samples from the high grade metamorphic Gfohl unit in Austria by Fuchs et al. (2005).

It is used in the manufacture of high grade porcelain. It is sometimes mistaken for sodalite and has been used as imitation lapis lazuli.

Sources of Dumortierite include Austria, Brazil, Canada, France, Italy, Madagascar, Namibia, Nevada, Norway, Peru, Poland, Russia and Sri Lanka.

TRADING AS TRUEBLUEOPALS / LIGHTNINGOPALS LLC

Shipping
Shipping provider Shipping to Australia Shipping to rest of world Combined Shipping (Australia) Combined Shipping (rest of the world)
Standard Shipping - Tracked
/ 4 days
/ 14 days
on orders with 2 items or more
on orders with 2 items or more
FedEx
/ 4 days
/ 4 days
on orders with 2 items or more
on orders with 2 items or more
DHL
/ 4 days
/ 14 days
on orders with 2 items or more
on orders with 2 items or more
Store
4.75-CTS DUMORTIERITE ROUGH SPECIMEN  RARE MINERAL  RG-4215 RAREGEMS
Qld, Australia
Owned by raregems
Recent Feedback
  • gerald-t
    gerald-t
    Positive

    Great specimen. Good size & colour Best Thumbnail I've seen in 35 years of collecting Can you provide details regarding location of find?

  • rw167-671
    rw167-671
    Positive

    Happy with purchase, arrived today. Thank you

  • rw167-671
    rw167-671
    Positive

    Happy with purchase, arrived today. Thank you

  • rw167-671
    rw167-671
    Positive

    Happy with purchase , arrived today. Thank you

Bids History (1)
nlara
nlara
9 months ago
Purchased from this seller previously

Why are users outbidding themselves?

Automatic Bid icon
Automatic Bid

When a bid is placed, this is the maximum amount a person is willing to bid for the product. Our system will then automatically bid on behalf of the bidder, incrementally increasing the bid up to the maximum to maintain their position as the highest bidder.

When there is an icon indicating 'Automatic Bid', it means our system is actively placing bids for the bidder based on their maximum bid. This may appear as if bidders are outbidding themselves, but it's simply a result of the system updating the bid to reflect the bidders maximum limit.

Audit

The Gemstone Sheriff program allows our members to request an audit on any product, which is completed by an independent Gemologist who assesses the accuracy of the item description and pictures.

Shipping Details

Costs:
Transit:
14 days via Standard Shipping - Tracked
Ships from:
Australia

Payment Options

  • stripe
This seller adds 0% tax to transactions in Australia.

Overview

Listing Type : Standard
Product ID : 2034122
Estimated RRP :
Starting Bid :
Starts : 28th March 2025 09:53 pm PDT
Ends : 11th April 2025 12:32 am PDT
* All prices are in USD

You may also like