Using a Blowpipe for Field and Lab Mineral Identification

Blowpipe Analysis for the Prospector in the field or lab

With the invention of modern instruments or methods the blowpipe has been largely ignored, and relegated to the dim past. That is too bad in another time not many years ago it was well know in prospecting as the leading edge tool for making an analysis in the field or lab. Although it was only capable of qualitative analyses it gave the assayer or prospector an idea of what elements the sample contained. There are still analysis kits available on the market that contain the blow pipe system. In the 1800s the blowpipe was used in the discovery of 15 elements. It was the invention of the Bunsen burner and spectroscopic analyses that finally ended the reign of the blowpipe. The author learned to use a blowpipe in a high school chemistry class because he had a chemistry teacher that encouraged him to become proficient with the use of blowpipe.

The blowpipe dates back to the land of Khem the ancient name for Egypt this same land lent its name to the word “Alchemist” and Chemistry. Because of its association with alchemy it fell into disfavor before being resurrected in the late 1600s. The Land of Khem was instrumental in giving us the modern science of Chemistry. The blowpipe reigned supreme as an analytical instrument until the 1860s when it was replaced with the Bunsen burner and the spectroscope. Because it created a small intensely hot flame, The blowpipe also had wide use in glassblowing and jewelry making as a means to solder or fuse small components to the piece of glass or metal being worked on.

TheA laboratory blowpipe is an instrument that is about a foot long usually made of brass tubing that is tapered down from a quarter inch opening at its rear to a pinhole opening at its front end. The pipe is usually bent at right angles about 2 inches from its front end. In use the blowpipe is used to blow an intensely hot flame from an alcohol lamp or candle to heat a sample placed on a charcoal or plasted block. The analysis takes place usually on the charcoal block although for certain analyses a plaster of Paris block with the intensely hot impinging on it with an intense stream of fire that is blown from an alcohol lamp, candle or kerosene lamp by blowing through the flame. This technique will create an intensely hot flame using a blowpipe.

By using a blowpipe on a small specimen of material that is being tested that is no larger then a pea the blowpipe is able to reduce it to a small sized shot of the metal in the specimen and a colored halo around the sample that precipitates onto the charcoal or plaster of Paris. By using both products found on the test block the user is able to be sure of what he has tested. The appearance of the aura is characteristic of the mineral being sampled.

The accompanying references give a good detailed explanation of using the blowpipe for field or lab analysis.

References:

Burchard, Ulrich, The History and Apparatus of Blowpipe Analysis, The Mineralogical Record,

A Brief History of Blowpipe Analysis,

Dana, James Dwight, Manual of Mineralogy, pages 67 to 71, 1865, New Haven Ct.

This is a reproduction of James Dwight Dana's monumental 'Manual of Mineralogy' and is well worth reading the whole thing. The description of blowpipe analysis in its hayday is on pages 67 to 71.