Many of the high refractive
index mounting media that were used for diatom slides in the
past are now unavailable. I have developed a high
refractive (1.70+) index mounting medium that is useful for
mounting diatoms. This material has been named Zrax and is
a condensation product between naphthalene (Enoz old fashioned
moth balls) and formaldehyde (Formalin MS - used as an aquarium
treatment). Zrax is similar to Hyrax, which is no longer
available, and Naphrax. It is reported that Naphrax was
unstable over time and deposited droplets, thus spoiling the
hard work involved in making the preparation. Zrax has shown no
such problems and produces a beautiful preparation. Zrax is
dissolved in toluene and is a clear very light yellow material
with a refractive index of greater than 1.70 in the solid.
It makes excellent diatom mounts and is used for arranged diatom
slides in addition to strews. For a descriptive page on Zrax in
pdf format, click here. For an excellent article on
making strew and selected diatom slides by Jim Solliday, click
High Refractive Index Mounting Media
One ounce bottles of Zrax without solvent are $40 postpaid from me(Bill Dailey)
Larger quantity 200 gram bottles are $225 plus postage. Email me
requirements. Klaus Kemp
(www.diatoms.co.uk) is a reseller for the UK and the European
Union. Contact Klaus for details. You will need to add toluene or
other organic solvent to dissolve the resin before use.
Toluene may still be available in your local hardware and paint
stores as a thinner or degreaser. Toluene can not be sent in the
US mail system. If you are unable to locate toluene, you can
substitute Xylene (Xylol). However you will need to warm your
slides to a slightly higher temperature to cure them since xylene
boils at a higher temperature than toluene. Another solvent you
can use is pure acetone. Make sure that you use pure acetone and
not a product that has water in it or that will spoil slides.
DON'T use alcohol or turpentine or mineral spirits, etc. They
won't dissolve the Zrax and will cause problems.
diatom mounting medium is Styrax which has a refractive index of
1.58. It is especially useful for highly silicified forms like
those found in fossil marine samples. It is available from Dr.
Stephen Nagy who maintains the Montana Diatoms
page. Other information and products related to diatoms will be
found here, as will some beautiful pictures of spectacular
arranged diatom microscope slides.
In the past I
offered Pleurax but I am no longer able to make it because it
causes me a severe allergic reaction similar to the blisters
caused by poison ivy.