Milk Glass
The white color is achieved through the addition of an opacifier such as tin dioxide or bone ash. White milk glass was first made in Venice in the 16th century, colors were introduced staring in the late 1700s. Colors include blue, pink, yellow, brown, and black. 19th-century glass makers usually called milky white opaque glass "bone glass"; the name milk glass is relatively recent.


Goldstone, Aventurine glass
Goldstone was invented in 17th century Venice by the Miotti family, who were granted an exclusive license by the Doge. Persistent folklore describes goldstone as an accidental discovery by an unnamed Italian monastic order or medieval alchemists, but this appears to be only a legend.
Antique Goldstone is usually a reddish-brown, containing tiny crystals of metallic copper that require special conditions to form properly. The final appearance of each batch is highly variable; the outer layers tend to have duller colors and a lower degree of glitter. The best material is near the center of the mass, ideally with large, bright metal crystals suspended in a semitransparent glass matrix. Beads are usually carved from this mass, not molded or blown.
By using minerals other than copper, Goldstone can be made in purple, blue, and green – these colors are rare in antiques but common in modern manufacturing. 
Opaline Glass
A decorative style of glass made in France from 1800 through the early 1900s, though it reached its peak of popularity in the 1850s and 1860s. The glass is opaque or slightly translucent, and usually white, although it can be found in green, blue, pink, black, lavender and yellow. It has a high lead content. The primary influences on this style of glass were 16th century Venetian milk glass, and English white glass produced in 18th century Bristol.
Opalescent types of glass and plastic are still made today, but antique opaline glass has more variation, which often gives it more 'fire' than modern glass. 
Pressed Glass
The first recorded showing of pressed glass beads was in 1829, at a trade show in Prague. By 1850, glass beads were being produced by the millions, and exported all over the world. Pressed glass beads became very popular because of interesting shapes including faceted surfaces.
Camphor Glass
A glass with a cloudy white appearance created by treating the object with hydrofluoric acid vapors, made in numerous Midwestern US facilities during the mid-19th century. Blue camphor glass, attributed to the Sandwich Glass Company, also exists but is extremely rare.
Saphiret Glass
Made in Gblonz, Bohemia (Czechoslovakia) in the mid 1800s through around 1910, Saphiret is highly collectable. Made by mixing colloidal gold into sapphire-colored glass, resulting in a brick red to brown glass that reflects a blue surface. Often found in brass or gold-filled settings, as this was ‘only’ glass.
The "Prosser" technique of pressing glass, invented in 1840, consists of molding a cold glass and ceramic paste under great pressure and then firing it. The finished product looks like porcelain and is often referred to as such. This method allows for only opaque colors, not fully transparent ones. In 1844 Jean-Félix Bapterosses patented a machine for making buttons using the prosser method - he also improved the plasticity of the glass paste by incorporating milk into it. Bapterosses started producing beads in 1860 - 1864. All Prosser beads have a seam running around the bead.
Swarovski Crystal
In 1892, Daniel Swarovski invented a machine that revolutionized the process of cutting crystal. The Swarovski company was founded in 1895. It's fairly easy to date swarovski beads by their shape and cut, the older designs are regularly retired and new designs added.
Aurora Borealis
The Aurora Borealis crystal finish was created in collaboration with Christian Dior in 1950. Widely available after 1955, this was the first of many metal-based finishes created by Swarovski for their crystal beads. Wildly popular in the 1950s and 1960s, and still in use.
AB is a finish on about half of the crystal. AB-2X covers the entire crystal.