There are several criteria which dictate the value and scarcity of early pharmacy bottles. These  criteria include, but are not limited to, composition, color, size, condition, age, and origin/provenance. The earlier glass bottles, know as "shop rounds" originate in England and the prime examples have unfinished open (aka "rough") pontils. (The pontil is the point on the base of the bottle where it was removed from the glassblowers rod. )On earlier glass bottles the pontil is rough, and can be quite sharp and cut flesh easily. Later bottles have the pontils ground smooth with the glass on the bottom. The shop rounds have painted gilt labels showing the substances contained within. They also typically have flat "ice cube" type stoppers. They are usually round but square ones are also common. The dating on these is circa mid 1800s with the earlier examples from around 1840. The bulk of these are clear glass but they can be found in a Bristol Blue Cobalt color as well which adds considerably to their value.  It should also be noted that a number of these cobalt examples are SYRUP Bottles, which can be identified from the SYR abbreviation of the labels as well as the fact that the stoppers are elongated with stems that protrude into the bottle body. The best examples of this type, that is to say a cobalt blue rough pontiled bottle with gilt label intact, should be valued at about $ 250.00 +/- 20% depending on size and condition.Later shop rounds had their labels either "applied" in which the label is raised from the bottle or recessed into the glass. As the labeling of bottles evolved, they were made by painting the names of the substances onto thin ceramic wafers which were then attached to the bottles using beeswax and then covered by a thin glass. These types of bottles, Label Under Glass Bottles, are commonly referred to as LUGs and form the basis of the American Pharmacy Bottle Industry. The most common makers of apothecary bottles in the US were WALTON & CO and WHITALL TATUM out of New Jersey, although they opened plants worldwide during their operations.  Probably now 8 out of every 10 American made bottles that you will encounter will be made by Whitall Tatum. (They will be embossed W T & CO on bottom), Of the American bottles, they are clear, amber, or blue in color. Amber s worth slightly more than clear, Blue worth considerably more. Many of the blue American bottles have the names of the contents embossed on the front rather than on labels, but both are available. The American Bottles come in two basic types, a TINCTURE TOP type which has the elonaged neck and narrow bottom stopper; and the SALT MOUTH which  has a wider opening to allow for insertion of a spoon. Some of the bottles (mostly oil extracts bottles) have pouring spouts and/or glass overcaps which add a bit to their value. I hope you find this synopsis useful.