Cut Gem Ian Robinson - Bespoke Gems
Precision Cut in the UK
Home Cut Stones About

8/3/2021 - Leuco Sapphire

Pure white sapphire - second design in my 'Apostate' series. Brilliant cut pavilion. A high crown with 8 narrow frosted parallel-sided facets.

---------------------------

7/3/2021 - Set a Topaz

Blue Topaz "Chrysanthemum Flower" in sterling silver crown setting with rabbit ear bail. Setting entirely handformed from sheet silver.

---------------------------

27/2/2021 :: Apostate - in green sapphire

Precision faceted green sapphire
Apostate - Green sapphire!

Lab green sapphire in my new 'Apostate' cut. Green sapphire is rather uncommon and expensive. Nice colour.

---------------------------

26/2/2021 :: Added Silversmithing Section

Under drop-down menu. Initial post shows construction of a heavy hand-formed silver crown collet.

---------------------------

29/1/2021 :: Something for the weekend sir?

Fluorite for faceting
Fluorite Rough, blue belgium approx 14mm wide, large piece approx 70mm wide.

Hmm, appearing to be between commissions time to try something new. Fluorite - crystalline calcium fluoride (CaF2) is a drop-dead gorgeous material. Not rare, it comes in many colours, some fluoresce, some change colour with temperature. Fluorite is rarely set in jewellery as it is rather soft so cut stones are generally bought as collector's pieces. Apparently can be tricksy to cut and polish. Somehow I don't think this will end well.

---------------------------

28/1/2021 :: Partially cut natural blue topaz

Precision faceted natural blue topaz gemstone
Blue Topaz - partially cut

Halfway through cutting a large natural blue topaz in Jeff Graham's 'Brilliant Pear' cut. The pavilion (bottom) of the stone has been cut. It will now be transferred to another 'dop-stick' to cut and polish the table (top). The faint marks are not on the surface rather the result of veils - imperfections within the body of the stone.

If you want a perfect crystal then one needs to cut lab-grown rather than natural stones.

---------------------------

28/1/2021 :: Silversmithing Tools Fetish

Just got some tasty new pliers - the two at the bottom. These are British made Maun parallel pliers with flat jaws. Used in silversmithing to bend metal without damaging the surface.

Silversmithing Pliers
You can never have too many pliers.

---------------------------

9/1/2021 - 3 Crosses

3 gemstones cut in my 'Iron Cross' design. Blue is lab-grown spinel, black is natural black spinel, clear is lab-grown 'white' sapphire.

The Iron Cross has been a German military award from 1877 to the present and its design may be traced back to the cross pattée of the 11th century Teutonic Knights of Jerusalem and earlier.

---------------------------

26/12/2020 - New Gem Design

Iron Cross Gemstone
Published a new design: ruby or black spinel?

---------------------------

30/10/2020 - On The Dop

Crusader Shield

A commission - will cut a couple extra in amethyst and sapphire.

22/10/2020 - Back to Cutting

Finished my gemstone faceting machine upgrade - encoder version 2.

High Resolution Inclinometer 1/40 degree, excellent repeatability.
Faceter Digital Encoder
Digital Encoder fitted to Polyhedron/Polymetric Faceter
Faceter Digital Encoder
US E6 Digital Encoder to Arduino

Taken a while as other things have intruded. Works rather nicely reading to 0.025o using a US Digital optical encoder interfaced to an Arduino driving a 1.5" colour OLED display. Hardware has been running for a year or two without problems. New version has a much better display and simpler interface. No longer needs a switch to enter calibration mode and can be reprogrammed in situ via the USB power cable - greatly easing calibration. The Arduino Uno shown was replaced by a Nano allowing the whole thing to be fitted into a smaller box - I still managed to botch the display cut-out though. Thanks to Tom Herbst for his elegant code which I brutally and inexpertly simplified. Write-up for UKFCG to follow.

Stone on the dop is one of a matched pair of Hanami (花見) Sapphires.

15/8/2020 - Must stop buying rough!

Some more Neodymium-doped Yttrium Aluminium Garnet (Y3Al5O12) arrived today. Unusual shape for a laser rod but I can cut nice rectangular stones from this.

Yttrium Aluminium Garnet

11/8/2020 - Soviet Era YAG

Just taken delivery of some Yttrium Aluminium Garnet (Y3Al5O12). From what I assume is a broken high-power laser rod. The provenance is interesting as I strongly suspect this came from the stockrooms of a soviet-era defense research establishment. Since the development of cubic zirconium YAG has fallen out of fashion as an exotic gem material - which does add rather to the rarity. :-)

Yttrium Aluminium Garnet

10/5/2020 - A Man of Wealth and Taste

'Lucifer' - cut in Indian black spinel.

I do like spinel feeling that the surface lustre is superior to sapphire. Black spinel has to be polished with great care as the smallest scratch is apparent. Was there any point cutting the pavilion (bottom) No - apart from a sense of completeness. In the video under bright light and high magnification it become apparent that the stone is actually a very deep red - to the naked eye appearing jet black. I think I'll set this myself when I can come up with a suitable design - thinking black silver spikes, gold & copper.

---------------------------

9/5/2020 - Green Sapphire Opposed bar Cut

---------------------------

26/1/2020 - On the Dop

Currently cutting a pink sapphire triangle.

Pink Sapphire Triangle

Pink Sapphire Triangle

---------------------------

31/8/2019 - Oxford Stone #2

Loosely based on a design by Marco Voltolini

Yellow smokey quartz fancy cut
Fancy Cut yellow Quartz

---------------------------

15/8/2019 - Oxford Stone #1

I'm cutting some stones for a display in the Oxford National History Museum. This is yellow smokey quartz from which I hope to cut something rather unusual......

Yellow smokey quartz for faceting
Yellow smokey quartz
Thanks you bernard
An Unusual Gemstone Cut

---------------------------

29/6/2019 - Blue Topaz Star of David - hmmm

Stars of David are very tricky to get right. This looks good in the flesh though not so good at high magnification. Whilst I can place facets to better than 1 /40 degree the slightest misalignment become apparent at high mag. I can now see why some faceters place the star in the pavilion (bottom) as the angles are less critical.

I think I'll leave them for the mo. I am prepared to cut one to commission but the cutting time may well be in excess of 20 hours - this will be expensive.

For the moment my religious/mystical are various crosses/crusader shields, Yin-Yang and the Lucifer cut.

Blue Topaz star of David
Blue Topaz - Star of David #1

---------------------------

23/6/2019 - Blue Topaz Star of David

I have received some blue topaz from a dealer in N.Z. Currently working on a matched pair of Stars of David which should look nice in this light blue.

Uncut Blue Topaz
Uncut Blue Topaz

Preparing to polish the pavilion on the first stone

Cut blue unpolished pavilion
Cut, unpolished pavilion - Blue Topaz

---------------------------

22/6/2019 - Rexy - Sapphire

'Rexy' by Robert Dodd - cut in sapphire

Rexy - Sapphire
Rexy - Sapphire

---------------------------

15/6/2019 - Smithsonian Bar - Tourmaline

'Smith Bar' by Jeff Graham - cut in natural moss tourmaline

---------------------------

17/2/2019 - Mexican Fire Opal

I have just received 65ct of very nice rough from New Zealand. I should be able to cut at least 6 nice stones from this.

Mexican Fire Opal Rough
Mexican Fire Opal Rough

---------------------------

14/2/2019 - Mythos Collection #2

Continuing with my aim of building up a portfolio of mythologically inspired gemcuts - I now have a couple of Stars of David, various pentagrams, the 'Lucifer' cut and crosses. I am presently working on a yin-yang in ametrine. Here is a 'crusader shield' the cross would stand out better in a lighter stone especially if left frosted. Unfortunately I neglected to clean the stone properly before filming. Maltese crosses may be a better way to go as the simpler cross would stand out more. Also my own 'flower pentagram' in pink sapphire.

---------------------------

14/2/2019 - Two sapphires - Star of David #1 and #2

The white (clear) is the classic design by Fred Van Sant, two tiers of facets on the crown are frosted to create a Star of David. For the second I slightly adapted the design, cut in blue sapphire to match the Israeli flag - a lighter blue may work better.

---------------------------

14/2/2019 - Faceting - high resolution protractor

Decided to retrofit an optical encoder to my facting machine as the cheap 'n cheerful one is playing up. I've ordered a 3600 cpr optical encoder from the US (US Digital E6), with quadrature encoding this should give a resolution of 0.025 degrees. I'll use an Arduino with a panel display for the readout and maybe fit a pressure sensor to the quill whilst I am at it. This probably means very little to most people - but its a cheap(ish) way of measuring angles on a machine bloody precisely.

Polyhedron faceter
My much adapted Polyhedron facter

---------------------------

23/08/2018 - Smoky Quartz - Test Cut

A quicky photo of recent test cut - included smoky quartz (i.e. the marks are internal not on the surface), design 'Smithsonian' Bar by Jeff Graham.

smoky quartz
Faceted smokey quartz, Smithsonian Bar by Jeff Graham

------ooo00O00ooo------

3/06/2018 - Padparadscha Sapphire - 'Alien Outpost'

5.5ct 10mm high, symmetrical. The cut is 'Alien Outpost' by Greg Glenn - a classic gemstone designer. 49 facets optimized for sapphire. This stone was very slowly cut, mostly on 3000 grit, polished on 8000 grit and finished on 100,000 grit using a ceramic lap for maximum sparkle and flatness.

sapphire1 sapphire2 sapphire3
Padparadscha Sapphire - Alien Outpost Design

------ooo00O00ooo------

2/06/2018 - Brazilian Amethyst - 'Cube Illusion'

An unusual and rather difficult cut. Reminds me of an Escher drawing, when moved the central cube appears and disappears. This particular cut is surprisingly tricky and rather time consuming, I went through a number of stones before I got it right. It took so long that I am unlikely to do another for some time. 9-9.1 mm high. A very deep brazilian purple.

cube Illusion 1 cube Illusion 2
Amethyst - Cube Illusion Design

------ooo00O00ooo------

9/5/2018 - More soviet surplus goodies

Postie today delivered a package from Russia. Various Lithium Niobate prisms for me to facet. Like the tantalate probably surplus from the high-tec defense programs of the 80's. A clear opto-electronic ceramic with a high refractive index - close to that of diamond. Rare stuff.

null rifle signature plot
one of a number of lithium niobate pieces for faceting.

------ooo00O00ooo------

6/5/2018 - Chillin with white sapphire

Relaxing with a change of scene. Continuing to cut a white sapphire which I have been neglecting under pressure of work- 'Sweetheart' cut - same size and cut as the one somewhere below.

null rifle signature plot
White sapphire on faceting machine.

------ooo00O00ooo------

2/4/2018 - A sapphire in a novel setting

'Sweetheart Cut' (design by the late Jeff Graham) 5ct sapphire cut by myself. I was going for a minimalist setting with the stone 'floating' above. Beveled sterling silver bar about 4cm tall. Rather pleased with how it turned out. The photo is a bit lousy but looks very tasty in the flesh.
Sapphire in a setting
Minimalist sterling silver bar setting.

------ooo00O00ooo------

3/3/2018 - Exotic Faceting Material

Postie delivered a package from Russia containing three pieces of Lithium Tantalate - LiTaO3. An exotic optoelectronic ceramic, little cut due to scarcity, high refractive index (2.2) and crazy high dispersion (0.128) - three times that of diamond. Given where it was posted from and the date of 1978 I suspect this is old stock from the soviet high-tec defense industry. Rare stuff, I will have to think carefully about suitable cuts.

LiTaO3 prism
Soviet military surplus - Lithium Tantalate

------ooo00O00ooo------