Beryl

Characteristics

• Habit - prismatic, sometimes long
• Form - heaxagonal or triagonal
• Hardness - 7.5-8 (quite hard)
• Cleavage - indistinct
• Fracture - uneven to conchoidal
• Streak - white
• Lustre - vitreous
• Colour - blue, green, yellow, pink, colourless

Beryl features.

Beryl samples from the day workshop.

Introduction

Before 1925 beryl was used only as a gemstone for jewellery. Other uses then discovered for the ore element of beryllium (pale green or white). [What are those uses??]

Most beryl is found in granites, granite pegmatites and rhyolites or metamorphic rocks, like schists. Has the presence of small impurities that give the colour. Often large transparent gemstones. Most are faceted but may also be fashioned into beads or cabochons (shaped and polished but not faceted; rounded convex obverse with flat reverse; used for opaque gems while faceting is for transparent ones). Due to the large crystals can be artistically carved esp. aquamarine. Most notable variety is the emerald but can fracture easily so care is needed when being set in jewellery and being worn.

Varieties

Emerald

[see paper handouts for more]

Green - coloured by chromium, with or without vanadium. Need to test to confirm its not Green Beryl (coloured by iron). The stones have many variations so it's difficult to find similar colours to make matching jewellery. Bright colour and the rarity of fine examples makes it sought after.

Properties:

• Brittle, often with fissures, easily chipped.
• Emerald cut - rectangular, step cut, corners truncated to give an octangonal shape. Produces a large top face to make the most of colour and modified corners to protect from chipping.
• Never put in an ultrasonic cleaner. Wash carefully. Do not subject to heat or use chemical/detergents which may damage the oil or fillings.

Lore: May birthstone; improves memory, protects from giddiness, improves eyesight and keeps away tempests, guards sailors and fishermen from mishaps if worn upon the chest.

History:

• Long history eg: Ancient Egypt 3500BC.
• Emperor Nero said to use emerald for watching gladiators in combat. Uncertain if it was used as a lens or a mirror. Appears to retain its hue in daylight and artificial light.
• Pliny said 'of all the precious stones, this is the only one that feeds the sight without satisfying it...it is refreshed upon being turned upon the stone'.
• Older stones were often pale & translucent. When the Spanish went to South and Central Americas in 1500s the found emerald in use. These new deposits produced huge quantities of emerald and were shipped to Europe.
• Columbia is still the most prestigious origin for emeralds since this time, producing magnificent gemstones.
• Other deposits are from India, Brazil, Zambia, Madagascar, Ethiopia, Pakistan.

Quality factors:

• Depth of colour and tone.
• Soft, rich blueish-green to green is highly regarded. Not too dark.
• Often has inclusions so better the clarity the more valuable. Clarity shouldn't be compared to stones like aquamarine.
• Locality is also a major price factor

Routinely treated with oils, resins and polymers to fill fractures and cracks. This hides fractures, improves clarity and colour, increases long term stability and improves appearance. This is considered acceptable as long as it is disclosed.

Many inclusions which are sometimes 'jardin' or garden of a gemstone. These can give softness to the appearance but may also indicate geographical origin. Notable inclusions = 3 phase inclusions - contains solid, liquid & gas. Common from Columbia but later discovered in other deposits, resulting in them not being so indicative.

Often imitated and grown in the lab. Syn. show little difference from the natural eg: Flux grown Lennix example and those hydrothermally grown. Telling difference:

• inclusions and other features
• filter developed by Gem-A in 1934 - Chelsea colour filter - designed (by B.W. Anderson & C.J. Payne) to separate natural from imitations. Under the filter the natural appears red due to the presence of chromium while other green stones will not. Yet some syn stones can show red and other naturals, like demantoid, can do so to a lesser degree. Chelsea filter is less important today but still used for the initial scanning of large parcels of gems.

City Lit course (June 2026)

Have a number of cracks so have been oiled for centuries - light will travel through the oil instead of bouncing off the surfaces of the cracks / crystals are relatively small so 3 carats is unusual / are graded by the eye as it's normal for them to have inclusions, while sapphire and ruby use loupe.

Art deco style of emerald cut is the sugar loaf cabochon, surrounded by diamonds / double claws are good for emeralds as less risky to the stone as it's softer / colour is worth 50% of the stone, looking for a deep colour.

1st synthetic emerald was c. 1895 and used frequently in art deco rings. Emerald synthetics did not have inclusions but now they can be created with inclusions, eg: the example with a veil like inclusions that I didn't see in the other stones.

Oiling is normal and considered a 'minor clarity enhancement' and more indicates probably resin (may see bubbles under the loupe).

Good alternative to the soft emerald is the green garnet. Garnet is rarely treated and has a good colour range eg: tsavorite

Columbian: 50% of the world's emeralds; anything from here may have resin instead of oil, so check; good sources are La Pita or Muzo mines, although Muzo is running out; treated with resin at source; bad for smuggling; typical pale colour; provide 65% of world market; 19% tax on gems which is generally ignored; want a certificate.

Zambian: the Zambian is more a true/traditional colour than the Columbian; struggle to get a rough of c.2 carat so will be expensive eg: 3.5 carat is c.£8000.

Thailand and China: produce a lot of synthetic ones, used in watches and jewellery.

Brazil: not as good as Columbia; bad working conditions and you'll get car jacked anywhere near mines - don't go; want a darker and brighter colour; half the price of Columbian and closer to Zambian prices; slightly fairer system and less of a family business.

Zambia: hazy looking stones; main selling company is Gemfields & is tied into the government, fairly fixed prices but can include some roughs; smuggling is bad (one guard per worker).

India & Pakistan: lower grade emeralds with more inclusions; black inclusions are typical of India.

Green Beryl

Green - coloured by iron. Need to test to confirm its not Emerald.

Red Beryl

Pinkish-red.

One of the world's rarest gems.

Aquamarine

Means 'Sea water' and is the March birthstone.

Is the most common of the Beryls. Large and cleaner crystals than emeralds. Found in cavities in pegatites or alluvial deposits.

Shades of pale blue to greenish-blue, deeper colours are more desirable and the best stones have strong colour & excellent clarity. Coloured by iron but much on the market is the result of heat treatment - where the original yellowish, greenish or blueish material is turned a stable blue. May see long parallel inclusions which are liquid & gas filled cavities called 'rain'.

Lore:

• treasure of mermaids
• keeps sailors safe at sea
• good for debaters
• useful for driving enemies away
• makes the wearer well mannered and to foretell the future

Occasionally used in ancient jewellery but only become popular in the last few centuries.

'Santa Maria' aquamarine is a deeply saturated blue gem found some years ago at Santa Maria Habira mine in Minas Gerais, Brazil. Phrase used when talking of the best. Even small stone from here are deep blue. Now fire aquamarine is found elsewhere but the trade still speak of Santa Maria as a celebration of colour and a verbal applied 'quality' definition.

Where found - Brazil, Kenya, Madagascar, Myanmar, Mozambique, Namibia, Nigeria, Russia, USA, Vietnam, Shigar in Pakistan.

Aquamarine at the Natural History Museum.

Heliodor

Means 'of the sun'.

Yellow - coloured by iron.

Morganite

Named after J.P. Morgan.

Pink to orange-pink - coloured by manganese.

Goshenite

This is its pure form and is colourless.

Arab Roots of Gemolgy

Some elements from 'Arab roots of gemolgy: Ahmad ibn Yusuf Al Tifaschi's Best Thoughts on the Best of Stones' (c.1240) trans. Samar Najm Abul Huda. The Scarecrow Press, London, 1998.

Emerald

Called zumurrudh. Ones found in sand (by seiving) are called fass and ones cut off from the vein (in the mines) are called qasab.

Pliny said it started as corundum (a gold base stone, the origin of all stones as gold is the leader of all molten substances) and heat changed it and colours intermingled. Emerald is brought from a mountain at the border between Egypt and Sudan, behind Aswan. Mines are located at 10 days walking distance from Qus, such as Wadi al Nahr.

Four varieties:

• zhubabi - most valuable, with the best properties, a deep green without any tinge of yellow, black or other colour, good clarity. Named after the colour of the big spring flies found in the field, not in the house. White tinge is the best and is called al 'Arabi (the Arabian). To test it is genuine the eyes of snakes pop out of their sockets on the spot when they look at it.
• rihani - light colour of basil leaves
• silqi - chard green colour
• sabuni - soap green colour, no value worth mentioning

Best stones have a big size and a straight undistorted crystal. Biggest defect is pleochroism, one spot shows a different colour. Other defects - crystal distortion (applies to any other transparect stone), and cracks within the stone, of which emerald is virtually never free. Characteristics include: soft and brittle and therefore light in weight, smooth and soft, inclusions of cracks which it is virtually never free, green colour increases and become clearer when it is foiled, disintergrates under fire, not stable under high pressure like ruby.

Strengthens the eyesight if one stares at it for a long time. Worn in a necklace or ring protects from epilepsy, if worn before the disease occurs and so sages would order kings to make their children wear the stone around their neck at birth. Beneficial against blood discharges, dysentery, stomach pains if placed over the stomach. Hung on the upper arm for protections and talismanic purposes and on the thigh to speed childbirth. All the properties are exclusive to the zhubabi kind of emerald, although as it is a noble stone of great benefits, the properties being inherent in large or small stones. The others three kinds are of no particular value.

Other stones that resemble emerald are jasper, green jade, peridot and green sapphire.