UMBA SAPPHIRES - The miners of the Umba Sapphire report that they have either lost the seam or the deposit has run out. I still have some stock in hand but this will possibly run out by the year end.
Virtually all the Umba Sapphires show a unique 'color-change'. That is, they appear to be one color in daylight and another under incandescent light. All due to the amounts of chrome in the stone.
Umba Sapphires must be the most difficult stones to describe color, because of the color-change' phenomena. These are no exception. I have tried my best to convey the colors seen firstly in natural light and next the change shown under artificial light. Because the stones are strongly dichroic, I have described the predominant color.

All the Sapphires have been graded AA where I cannot accurately observe any faults - they could be AA+ in grade.

MADAGASCAR GLASS-FILLED RUBIES Read on to understand and to become fully conversant as to what 'Glass Filled' means.
First some background - Madagascar miners have been finding large deposits of a dark red Ruby, so dark that much of it couldn't be utilized in cutting. For the last few years, the cutters in Thailand have been working on a process to lighten this Ruby. .The rough is treated , together with lead glass, in a very high, prolonged heat process and under a strong vacuum. This has resulted in the superb red-pink color which shows amazing fluorescence under incandescent light The lead glass, I am told, was supposed to fill any fractures. Under a microscope, some actual fusion of cracks has been noted in similar rough so you can imagine the heat these stones are subjected to. This treatment is now being used for the new Ruby deposits found in Mozambique. The upshot is that, although these Rubies are treated, they are not synthetic and cost a fraction of what you would pay for untreated stones of similar color.
More of these stones (larger sizes) on our Tanganyika Trading plate
Click onto www.gia.edu/research-resources-from-research/index.html for further information and for the comments regarding this process and their suggested wording for the treated/cut stone

Ruby - Glass filled

Ref	Status	Grade/Total	$ per	Total	Stone	Color	Country
No.		weight	carat	price	type	and remarks	of  origin
1		5.44 ct AA	$45.00	$245.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
2	sold	6.57 ct AA+	$65.00	$427.00	Sapphire	an outstanding, superb medium-blue stone	Tanzania
3		5.12 ct AA	$60.00	$307.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
4		6.07 ct AA+	$55.00	$334.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
5		5.20 ct AA	$60.00	$312.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
6		6.04 ct AA	$45.00	$272.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
7		5.77 ct AA+	$50.00	$289.00	Sapphire	a pretty, medium-light blue-purple color	Tanzania
8		3.69 ct AA	$25.00	$92.00	Sapphire	a medium blue to light purple	Tanzania
9		5.31 ct AA	$45.00	$239.00	Sapphire	an attractive light lilac-purple color	Tanzania
10	sold	8.36 ct AA+	$55.00	$460.00	Sapphire	a lovely, medium-light blue-purple color	Tanzania
11		6.92 ct AA	$55.00	$381.00	Sapphire	a very pretty, medium-strong blue color	Tanzania
12		4.74 ct A+	$50.00	$237.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
13		4.45 ct AA	$30.00	$134.00	Sapphire	a medium-light blue to light purple	Tanzania
14		6.45 ct AA	$50.00	$323.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
15		5.94 ct AA	$50.00	$297.00	Sapphire	a medium blue to light purple color change	Tanzania
16		3.82 ct AA	$30.00	$115.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
17		6.63 ct AA+	$35.00	$232.00	Sapphire	a lovely, medium-light blue color	Tanzania
18		6.37 ct AA	$35.00	$223.00	Sapphire	a medium-light blue to light purple	Tanzania
19		3.64 A+	$43.00	$157.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
20		4.79 ct AA	$30.00	$144.00	Sapphire	a medium blue-purple to purple change	Tanzania
21	sold	6.30 ct AA+	$40.00	$252.00	Sapphire	a very clean stone, odd yellow-brown color	Tanzania
22		2.54 ct A+	$40.00	$102.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
23		8.39 ct AA	$55.00	$461.00	Sapphire	a lovely, medium-light blue-purple color	Tanzania
24		3.85 ct A+	$40.00	$154.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
25		4.00 ct AA+	$18.00	$72.00	Sapphire	a pretty, medium-strong blue stone	Nigeria
26	sold	3.98 ct AA	$30.00	$119.00	Sapphire	an attractive light lilac-purple color	Tanzania
27		6.89 ct AA	$55.00	$379.00	Sapphire	a lovely, bright, strong purple color	Tanzania
28		3.95 ct AA	$25.00	$99.00	Sapphire	a medium-light blue - no color change	Tanzania
29		5.96 ct AA	$50.00	$298.00	Sapphire	a medium blue to purple change	Tanzania
30	sold	6.17 ct AA	$55.00	$339.00	Sapphire	a lovely, medium-light blue color	Tanzania
31		4.19 ct A+	$50.00	$210.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
32		4.36 ct AA	$35.00	$153.00	Sapphire	a medium purple-blue to purple change	Tanzania
33	sold	6.55 ct AA	$50.00	$328.00	Sapphire	a rich purple color, very pretty	Tanzania
34	sold	4.60 ct AA	$18.00	$56.00	Sapphire	a medium-light blue to light purple-pink	Tanzania
35		5.00 ct AA	$60.00	$300.00	Sapphire	a lovely, natural medium pink color	Tanzania
36		3.88 ct AA	$40.00	$155.00	Sapphire	a medium-light blue to light purple	Tanzania
37		4.66 ct AA	$40.00	$186.00	Sapphire	a medium-light purple-pink color	Tanzania
38		3.65 ct AA+	$50.00	$267.00	Sapphire	Winza - a medium purple-blue color	Tanzania
39	sold	7.83 ct AA+	$55.00	$431.00	Sapphire	a lovely, bright, strong purple color	Tanzania
40		8.28 ct AA	$55.00	$455.00	Sapphire	a lovely, medium-light blue color	Tanzania
41	sold	5.91 ct AA	$55.00	$325.00	Sapphire	a rich purple color, very pretty	Tanzania
42	sold	6.92 ct AA	$55.00	$381.00	Sapphire	a bright, medium-strong blue color	Tanzania
43		4.46 ct AA	$20.00	$89.00	Sapphire	an odd-looking Winza, dark green-pink hue	Tanzania
44		7.11 ct AA	$55.00	$391.00	Sapphire	a very pretty medium-light blue, purple hue	Tanzania
45		4.75 ct AA	$40.00	$190.00	Sapphire	a medium-light purple-pink color	Tanzania
46	sold	5.45 ct AAA	$55.00	$300.00	Sapphire	a medium-light sky blue color	Tanzania
47		3.97 ct AA	$35.00	$139.00	Sapphire	a medium-light blue, touch green	Tanzania
48		6.07 ct AA	$50.00	$304.00	Sapphire	a medium-light sky blue color	Tanzania
49		4.61 ct AA	$40.00	$184.00	Sapphire	a lovely, medium-light blue color	Tanzania
50		4.34 ct AA	$30.00	$130.00	Sapphire	an attractive light lilac-purple color	Tanzania
51		6.66 ct AA	$55.00	$366.00	Sapphire	a medium-light purple, very attractive	Tanzania
52		5.67 ct AA	$55.00	$312.00	Sapphire	a lovely lighter purple-blue color	Tanzania
53	sold	5.08 ct AA	$50.00	$254.00	Sapphire	a lovely lighter purple-blue color	Tanzania
54		5.13 ct AA	$50.00	$257.00	Sapphire	a very attractive medium-light blue stone	Tanzania
55		6.49 ct AA	$45.00	$292.00	Sapphire	a lovely, medium-light blue color	Tanzania
56		3.80 ct AA	$40.00	$152.00	Sapphire	a medium blue to light purple	Tanzania
57		4.58 ct AA	$45.00	$206.00	Sapphire	a medium-light purple, very attractive	Tanzania
58		7.74 ct AA	$40.00	$310.00	Sapphire	a medium light blue - no color change	Tanzania
59		4.18 ct AA	$40.00	$167.00	Sapphire	a medium-light blue to light purple-pink	Tanzania
60		4.26 ct A+	$50.00	$213.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
61		6.73 ct AA+	$55.00	$370.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
62		7.07 ct A+	$60.00	$424.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
63		3.94 ct A+	$40.00	$118.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
64		4.04 ct AA	$30.00	$121.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
65		3.57 ct AA	$40.00	$143.00	Sapphire	a very attractive medium-light blue stone	Tanzania
66		6.47 ct AA	$55.00	$356.00	Sapphire	Winza -a pink stone, very slight blue	Tanzania
67		5.28 ct AA+	$55.00	$290.00	Sapphire	a light blue to light purple change	Tanzania
68		3.29 ct AA+	$25.00	$82.00	Sapphire	a medium-strong blue stone	Madagascar
69	sold	3.96 ct AA	$10.00	$40.00	Sapphire	a medium-light blue stone, touch gray	Tanzania
70		3.18 ct A+	$40.00	$127.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
71		2.86 ct A+	$40.00	$114.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
72		2.82 ct A+	$40.00	$113.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
73		3.83 ct AAA	$25.00	$96.00	Sapphire	a pretty, medium lilac blue stone	Tanzania
74		3.99 ct AA	$40.00	$160.00	Sapphire	a medium-light blue to light purple	Tanzania
75		5.72 ct AA	$50.00	$286.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
76		3.15 ct AA	$40.00	$126.00	Sapphire	a superb, rich blue color, center black spot	Madagascar
77		4.02 ct AA	$30.00	$121.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
78		5.54 ct AA+	$50.00	$277.00	Sapphire	a bright, lighter yellow stone	Tanzania
79	sold	6.74 ct AA	$50.00	$337.00	Sapphire	a strong blue touch of green	Madagascar
80		4.46 ct AA	$40.00	$178.00	Sapphire	a very attractive bright, light blue color	Tanzania
81		4.07 ct AA+	$35.00	$142.00	Sapphire	a medium blue to light blue color	Tanzania
82		4.39 ct A+	$50.00	$220.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
83		4.12 ct AA	$15.00	$62.00	Sapphire	a medium purple-blue to purple change	Tanzania
84		4.19 ct A+	$50.00	$210.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
85		3.56 ct AA	$40.00	$142.00	Sapphire	a medium-light blue to white	Tanzania
86		4.65 ct AA	$45.00	$209.00	Sapphire	a very pretty, medium yellow color	Tanzania
87		5.16 ct AA	$35.00	$181.00	Sapphire	a light blue to purple change	Tanzania
88		4.49 ct AA	$30.00	$135.00	Sapphire	a light, lavender-blue color	Tanzania
89		5.25 ct AA	$50.00	$263.00	Sapphire	a medium purple-blue to purple change	Tanzania
90		4.32 ct AA	$35.00	$151.00	Sapphire	a pretty, light blue, touch purple	Tanzania
91		7.42 ct AA	$50.00	$371.00	Sapphire	a medium-light blue-purple stone	Tanzania
92		4.46 ct AA	$25.00	$112.00	Sapphire	a medium blue to purple change	Tanzania
93		5.00 ct AA	$55.00	$275.00	Sapphire	a pretty, medium-light purple-blue stone	Tanzania
94		6.02 ct AA	$25.00	$151.00	Sapphire	a medium purple-blue to purple change	Tanzania
95		5.08 ct A+	$50.00	$254.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
96		6.20 ct AA+	$55.00	$341.00	Sapphire	a lovely lighter purple-blue color	Tanzania
97		3.58 ct A+	$40.00	$143.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
98		6.61 ct AA	$45.00	$297.00	Sapphire	a lovely lighter purple-blue color	Tanzania
99		4.43 ct AA	$35.00	$155.00	Sapphire	a pretty, medium blue color	Tanzania
100		3.58 ct AA	$40.00	$143.00	Sapphire	a bright, light blue-purple stone	Tanzania
101		6.71 ct AA	$45.00	$302.00	Sapphire	a lovely lighter purple-blue color	Tanzania
102		4.79 ct A+	$50.00	$240.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
103		4.24 ct AA	$30.00	$127.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
104		6.09 ct AA	$50.00	$305.00	Sapphire	a very pretty, medium-light blue-purple	Tanzania
105		3.34 ct A+	$43.00	$144.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
106		3.56 ct AA	$30.00	$107.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
107		4.08 ct AA	$30.00	$110.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
108		3.16 ct AA+	$35.00	$240.00	Sapphire	a medium-light blue-green color	Tanzania
109		3,.28 ct A+	$43.00	$141.00	Ruby GF	a strong, fluorescent red-pink color	Madagascar
110		6.54 ct AA	$40.00	$262.00	Sapphire	a light blue to light purple change	Tanzania
111		5.09 ct AA	$50.00	$255.00	Sapphire	Winza -shows a mix of pink and blue colors	Tanzania
112		5.25 ct AA	$50.00	$263.00	Sapphire	Winza -a blue center, with pink surround	Tanzania

Cutting and Polishing Sapphire and Spinel - Barry Bridgestock

Cutting and polishing sapphire and spinel need not be much more difficult than dealing with other gems. Cutters
should be aware of the fact that spinel and sapphire have a softer and harder cutting direction. Care must be taken
to prevent overcutting when cutting in the softer direction. An ink mark on the dop to indicate the softer direction can
serve as a reminder. After finishing the cutting of the facets on a broken-in solid steel Crystalite 600 lap, I prepolish using 14,000 Crystalite pump spray diamond and white vinegar sprayed on a ceramic lap. I prepolish until the 600 scratches and ALL pits are gone, leaving each facet with a greasy looking finish because of the fine 14,000 scratches.
I then remove these fine scratches using 50,000 Crystalite pump spray on a corian lap. I use bottled water from a spray bottle as a coolant and do not have to apply a thin coating of wax as suggested by the manufacturer of the corian lap.
Finishing the table facet requires one additional step. Linde A with a white vinegar spray on a different corian lap. Using the corian lap will preserve the facet flatness produced by the ceramic lap. Corian laps are available from the Jarvi Tool Company, maker of Facetron, and giving these stones extra brilliance. It pays to shop around for ceramic laps and it is not necessary to have the most expensive ceramic lap made for prepolishing with 14,000 diamond.

Please feel free to offer suggestions or additions. I don't think it's common knowledge that you can use Linde A to polish sapphire. I certainly didn't know it until I tried it out of shear desperation last summer.