THE GEM-STONES OF THE HIMALAYA

DR. A. M. HERON.

THE Himalayan region is strikingly poor in minerals of economic value. As the valleys and the lower ranges are well-populated and constantly traversed by keen-eyed hillmen herding stock or on shikar, there is little likelihood that important deposits of well-known or conspicuous minerals can have escaped notice in the more frequented tracts. It is otherwise, however, in the case of rarer minerals, the uses of which are unknown to the people, and in the remote and untravelled wilderness near the realm of snow, where much may still be undiscovered.

Precious and semi-precious gem-stones are, from their beautiful colours, the most conspicuous of minerals, and the ease with which they are collected and transported enhances their lure in the eyes of the amateur prospector. I have therefore put together some particulars of the known occurrences in the Himalaya, as an indication of what may be found.

The majority of gems, other than diamonds, into the origin of which we need not enter, are found in pegmatites, crystalline marbles, and gneisses. These rocks are found in the Great Himalaya range from end to end, and anywhere within this vast belt gems may occur ; but they are special chemical compounds produced in the earth's laboratory by unusual combinations of circumstances, about which we know little. In consequence, although the parent rocks are common, the species of mineral to which precious stones belong occur sparsely and erratically ; and still rarer are those clear and well- crystallized specimens from which alone gems can be cut.

Gneisses are grey rocks consisting mainly of quartz, felspar and mica, and are characterized by a streaky or banded texture. They are the result of the intense heating, compression, shearing and re- crystallization of either sedimentary rocks, such as shales, or igneous rocks of the granite type. Most gneissic complexes probably comprise both, i.e., very highly altered shales, intimately injected with granite veins. Marbles, or coarsely crystalline limestones, similarly result from the heating of ordinary limestones, whereby the finely divided calcium carbonate of the original rock is re-crystallized in a coarse sugary texture, and the impurities separate out as crystalline oxides and silicates. Gneisses and marbles often compose the deeply-folded and crushed cores of mountain ranges, as well as vast areas of the more ancient rocks. In mineral composition pegmatite is akin to granite, consisting in the main of quartz and felspar, but is coarser in crystalline grain, and carries a greater variety of accessory minerals. It usually occurs in white veins ramifying through other rocks, into which it has been injected in a molten state. Pegmatite is supposed to have been the residual liquid remaining after the principal mineral constituents, quartz, felspar and mica, have crystallized from deep- seated masses of molten granite, and, as these masses contracted on cooling, has been squeezed out from them into the surrounding rocks, carrying with it much of the unusual ingredients of the granite. On the slow cooling of this complex molten mixture in veins, it solidifies, by the separation of its component minerals, as more or less perfect crystals.

The best place to search for gems is not in their matrix, but amongst the gravels, moraine and scree, which collect below slopes where such rocks crop out, and in the beds of streams draining them. Under the action of frost, rain and sun, the rocks slowly disintegrate, and in time are washed away as sand and mud, while the gems, being in their nature almost indestructible, tend to remain near their place of origin. A natural concentration thus takes place and the searcher has a far better chance of finding them in such situations than where they are sparsely scattered through the matrix, from which they can be extracted unbroken only with difficulty.

Sapphires were first brought into Simla early in 1882, by traders from Lahul, who stated that a landslip had laid bare the rocks beneath the soil, thus disclosing the presence of the gems. Until guards were posted over the locality by the Maharajah of Kashmir, large quantities of the stones were brought to Simla, and sold at absurdly low prices, such as a rupee a seer. Originally they were stated to have come from the village of Padam in Zaskar, owing to confusion with the true locality, which is the district of Padar in the Chenab valley (Kishtwar). The mines are in a small upland valley below the Umasi La* on the Great Himalaya range, at an altitude of 14,000 feet above sea-level, and 2500 feet above the village of Sumsam or Soomjam (latitude 33° 25' 30", longitude 76° 25' 0"), on the southern slopes of the divide between Kishtwar and Zaskar. Sumsam is on the Bhutna river, a tributary of the Chenab.

In 1888 Mr. T. H. D. La Touche11, of the Geological Survey of India, examined the deposit at the request of the Kashmir Durbar, as the revenue from it had been diminishing steadily. The rocks of the valley are coarse biotite-gneisses, in places crowded with garnets, and have, interbedded, a band of crystalline limestone and masses of kupfferite. Through these gneisses were intruded the dykes of coarse pegmatite in which the gems occur. This pegmatite consists chiefly of quartz, white felspar and black mica, with, as accessory minerals, large crystals of black tourmaline, light green euclase, kyanite, and corundum. Corundum is essentially the same mineral as ruby and sapphire, but is the opaque, non-precious variety used for abrasive purposes. Chemically, corundum, ruby and sapphire are alumina ; the difference in colour is supposed to be due to minute traces of chromium in the ruby and titanium in the sapphire. The " emery⁹⁹ of commerce is impure corundum. In the pegmatite itself, sapphires are very scarce and local, and the output of stones has come almost entirely from a narrow strip of debris, weathered from the pegmatite in the steep slopes along the northern side of the valley. The yield of sapphires decreased towards the lower end of the deposit, and also rapidly from the surface downwards ; below a depth of three feet none were seen.

La Touche constructed a simple apparatus in which the debris could be washed and the sapphires picked out. Most of the stones were small fragments, some not much larger than a pin's head, and crystals, the great majority showing poor colour and being of little value as gems. Occasionally, however, a larger stone of good colour was found. In 1887 the largest weighed about 6 oz., and was partly of a very brilliant colour ; but in 1888 the largest weighed only 104 grains, and very few were of more than 50 grains in weight. Much finer stones were found when the mine was first discovered, and La Touche was shown in the Treasury at Jammu some which measured 5 inches in length and 3 in breadth ; and though all of them shaded off into white at either end of the crystal, still some very fine gems could be cut from them.

The valley is under snow except during the months of July, August and September. In 1888, the year of La Touche's visit, the working season lasted from the 17th July to the 29th September, and the total quantity of corundum and sapphire obtained in that time was 42 lbs., of which about a quarter would be commercially valuable, but the average weight of the stones, calculated by La Touche from the results of 25 days' working, was not more than 10 grains. For some years the Durbar derived a considerable revenue from the mines, which were then abandoned under the impression that they had been worked out. In 1906 work was re-started by the Kashmir Mineral Company, and at first several valuable stones were obtained. Very soon however the production again fell off, and ceased in 1908. In 1906 the output was valued at £1327, and in 1907 £3144. One stone sold for £2000. In the summer of 1927 the deposit was again worked experimentally, with good results, by the Mineral Survey of Kashmir and Jammu under Mr. C. S. Middlemiss. It is evident that the area has not been exhausted, for elaborate policing has become necessary to prevent stealing. A few pale rubies, and red and green tourmalines have also been found near the mines.

La Touche investigated a beryl locality situated at an altitude of 12,000 feet, and four miles to the west of Matsel (or Machel), a village on the Bhutna river four miles below Sumsam. The few beryls found were .very poor in colour, bluish-green shading into white. He was shown a few sapphires, of a blue colour shading to a greener tint, in a block of granite lying on the moraine near the head of the glacier which descends from the southern side of the Hagshu La, one of the passes leading from the Bhutna valley into Zaskar.12 He was informed that sapphires had been found above the monastery of Bardun in Zaskar. Calvert, in his book Vazeeri Rupi (Kulu), reported that he found sapphires on the ascent to the Hamtah pass (32° 16'; 77° 21'; map 52 H/sw) in Kulu, but the statement requires confirmation, as the specimens do not appear to have been shown to a competent authority.

Aquamarines occur at Daso, in the northern Shigar valley of Baltistan, and were first discovered in 1915 by Lala Joti Prasad, of the Mineral Survey of Jammu and Kashmir State, excavated by him in the following year, and examined by Mr. C. S. Middlemiss13 in 1917. Daso (35° 43'; 75° 31/ ; map 43 M) lies at a height of 8300 feet on the Braldoh river a few miles above its junction with the Shigar, and the aquamarines, like the sapphires already mentioned, occur in veins of pegmatite which traverse the prevailing biotite-gneiss of the region. The largest veins of pegmatite are the coarsest, and are the most productive in aquamarines. The commonest minerals are quartz and felspar, after them tourmaline and muscovite, and then beryl (or aquamarine) and garnet. Beryl is the mineral species (a complicated silicate of aluminium and beryllium) of which emerald and aquamarine are the clear gem varieties. The green colour of emerald is believed to be due to minute traces of chromic oxide, and the blue-green of aquamarine to iron. The central portions of the large veins are sometimes composed essentially of felspar, and in these the beryl prisms are closely set. Whilst most of these are common opaque beryl, or only a translucent variety, a few are transparent enough for cutting ; the latter are usually found projecting as beautiful crystals into cavities in the masses of felspar. Besides the transparent aquamarine and the common, almost opaque beryl, there occurs an intermediate translucent variety of delightful deep green colour, suitable for buttons and beads.

The size of the opaque and translucent beryls is generally from ½ inch to 2 or 3 inches in width, and from 2 to 6 inches or more in length. The transparent aquamarines are smaller as a whole, averaging from ½ inch to 1 ½ inches wide and 2 to 3 inches long in the more perfect specimens. One exceptionally large crystal, 10 inches long and 5 inches wide, weighing about 13 lbs., was obtained in 1915.

The Daso aquamarines are of a pale, delicate tint, and of excellent limpidity, but the depth of colour is usually less than is called for by the present vagaries of fashion. By artificial light the tint is considerably deepened, and some of the larger pendant forms on view at the Wembley Exhibition in 1924 were much admired.

In ten days' experimental working, employing 25 men at a total cost of Es. 178 for wages, explosives and fuel, about 1760 cubic feet of pegmatite were excavated, yielding 3100 grammes (6 lbs. 13 oz.) of clear aquamarine, 3350 grammes (7 lbs. 6 oz.) of the intermediate translucent variety, and about 102 lbs. of rough beryl. Reckoning one carat at 0.20 grammes or 3.1 grains approximately, large pieces of aquamarine, uncut, were sold at 6 annas a carat, small pieces at 2 annas a carat, and large pieces of the translucent beryl at an anna a carat ; the total value of the ten days' takings was reckoned at Rs. 4577, from which has to be deducted transport, supervision, sale charges and profits. Cost of transport from the mines to the railway is Es. 9-4-0 per maund (Rs. 10-8-0 per cwt.). Cut stones of the best quality fetched, in 1918, Rs. 2-8-0 to Rs. 3-12-0 per carat in India as sold to dealers. The mines produced 20 lbs. of stones in 1920, and 55 lbs. in 1921. The deposits have only been superficially opened up and a long life for these mines is anticipated. In 1915, 31475 cwt., and in 1916, 4.13 cwt. of beryl of varying quality, were obtained in Skardu, and are said to have been sold for several thousand rupees.

Beryl-bearing pegmatites are not confined to the village of Daso, but are found within a mile or two ; and beyond this again they have been reported from the Basha valleys and the Rondu region, but it does not follow that all these localities will yield the gem variety of aquamarine.

There is another locality in which precious stones occur, though at present little is known about it. Rubies, spinels and garnets, with some sapphires and even, it is said, emeralds, are mined at Jagdallak (34° 22' ; 69° 48') situated at the crest of the Siah Koh range in Afghanistan, about 5 miles to the west of Kardeathal, in a belt of highly, crystalline limestone altered by granite intrusions. The rock is broken by hand and the gems extracted.*

In the Himalaya there is only one record, and that a very doubtful one, of the occurrence of diamond. Some small ones, supposed to have been found in a hill-stream near Simla, are preserved in the Geological Survey Museum at Calcutta. This find is mentioned in a letter to the Times of 7th September, 1872, but no details are given.

The semi-precious stones, turquoise and jade, are not worked in the Himalaya, but are brought through the mountains. The turquoise, which is almost universally worn as an ornament by hill-women, and is used in a crushed state for mosaic-work by the silversmiths of Kashmir, probably comes from the mines of Nishapur iu Khorassan, that is, when it is not artificial. The mines are situated in a ridge above the village of Maden (36° 28' ; 58° 20'), 32 miles north-west of Nishapur, and the turquoise occurs in trachyte breccias, associated with limestones and volcanic ash beds. A detailed description of the working of the mines and of the economics of the industry has been given by General A. Hontum Schindler,* who was in charge of the mines in 1882-83. The workings consist of labyrinthine shafts and galleries in the hillsides at heights of 4800 to 5800 feet above sea-level, and there are alluvial diggings at the foot of the hills in the detritus derived from the turquoise-bearing rock; in these alluvials the best stones are found. About 200 men were employed in General Schindler's time, and the output, valued at the mines, averaged 25,000 tomans annually.

Lapis lazuli, from which the artists' ultramarine was made, and which is known in the bazars as lajward, used to be imported into India from the mines of Firgamu in Badakshan, now discontinued. The mines are described by Wood, in the narrative of his journey to the source of the Oxus in 1838. This mineral is rumoured to have been found in Hazara and Khelat, but it is liable to be confused with the much commoner basic copper carbonate, azurite, as has also happened in the case of turquoise.

True jade (nephrite) has been worked for many centuries in the Kara-kash valley in Southern Turkistan. The jade of China is chiefly the closely allied mineral jadeite, which comes from the Mogaung division of the Myitkyina district of Upper Burma. The softer serpen- tinous mineral called bowenite passes under the name of sang-i-yeshm on the North-West Frontier, and is evidently regarded as a poor variety of jade, though its characters are unmistakably distinct.

North and east of the gold mine situated three miles north of Kandahar, both chrysolite, in beautiful bright green and yellowish crystals, and chrysotile in lumps of a light green or yellowish colour, occur in basalt. Chrysolite is a transparent variety of olivine, which when dark green is the " peridot " of jewellers ; and chrysotile is a fibrous serpentine allied to asbestos, resulting from the alteration of the olivine of the basalt. Both minerals are used locally for beads: for rosaries, the former being the more appreciated.

Rock-crystal (clear quartz) is used for cheap jewellery in Kashmir, and an output of 24 lbs. was reported from the Skardu tahsil in 1921. Jasper, a massive variety of quartz, opaque and strongly coloured by impurities, is widely distributed in the Himalaya, and used locally for beads and other ornaments.

Garnets are very common and widely distributed amongst the schists and gneisses of the Himalaya, but have not been used for jewellery, as they are small and of poor quality.

It may be noted that the blue mineral kyanite, which is opaque and rather soft, and is seldom used as a gem, has often been mistaken for sapphire. It is particularly abundant in the schists and granite of Bashahr. Amethyst, a violet form of clear quartz, which is found at several localities in the valley of the Sutlej river in Bashahr,15 has also been confused with sapphire, and the pistachio-green mineral epidote is liable to be taken for jade.

From the above notes it will be clear that only the sapphire and aquamarine mines of Kashmir are of any real economic importance. However, great tracts of the Himalaya are as yet unprospected, and though the Himalayan Club would be the last to foster among its members that gambling instinct which characterizes the true prospector, and would deprecate the idea that a fortune is to be picked up as an accompaniment to a mountaineering tour, nevertheless a search for beautiful minerals lends an interest and perhaps even a mild excitement to wanderings over the stony pastures and bare rock which come between the forest and the snow. The chances of finding anything of value are remote, but even mineralogy may perchance be caught up in the net of the Club's activities.

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