1. Guide to Identifying Terrigenous and Biogenous Sand Particles
Use with Sand Lab #2

2. Roundness of Grains Angular Grain Well rounded grain
Roundness of grains can give information on how far the sediment has traveled from it’s source.
Roundness can also give information on how long a sediment has been residing in a given environment.

3. Terrigenous Sediments: land derived sediments
Rocks and minerals.
Can be continental sediments or volcanic sediments.

4. Basalt Sand (terrigenous):
Black to dark gray
Dull to shiny
Angular to rounded
Main component of black sand
Mainly Hawaiian Beaches
Volcanic origin
Usually found with green olivine grains & volcanic glass.

5. OLIVINE SAND Olivine (terrigenous): Translucent Glassy
Green to reddish-brown in color
Associated with basalt volcanoes
Usually found with basalt and volcanic glass

6. Volcanic Glass - (terrigenous):
Also known as obsidian
Associated with volcanic activity
Usually very angular in shape with a glassy luster.
Can be translucent if shard is thin enough.

7. Quartz Sand – (terrigenous):
Translucent to opaque white
Glassy luster
Angular to rounded grains
Most common mineral in continental beaches. No volcanic activity
Quartz can sometimes be stained red by rust.

8. Granite Derived Sands:
Mica Sand
Granite Derived Sands:
Although quartz is the most common mineral from granite, mica and garnet are also found in many sands.
Mica is flat and shiny with a copper luster
Garnet is deep reddish-brown with a glassy luster.
Granite
Garnet Sand

9. Biogenous Sediments: biotic sediments
Hard parts from living things. Such as:
Coral
Shells
Spines
Operculums (cat’s eyes)
Sponge Spicules
Plankton shells (bloody eye)

10. Coral Fragments:
Can be cream to white in color
Porous (holes)
Polished
Most of the time the grains are angular.

11. Pieces of shells:
Snail shells
- rounded shell fragments

14. Urchin spines suggest a rocky beach habitat
Urchin spines suggest a rocky beach habitat. Purple spines are found in temperate areas where striped are tropical.

16. Snail Operculum

18. Foraminifera-Plankton Shells
Tiny shell-like sediments that can be found anywhere.
Foraminifera

19. More Foram Sand (plankton shells)
“Bloody Eye” foram shells
Sponge Spicule

20. Sand from Bali
Predominately plankton shells
Snail Shell
Urchin Spine

21. Hydrogenous Sediments - Ooids
Ooids of the Bahamas
Ooids form in place and are NOT transported to the beach.
They are hydrogenous sediments that form similar to a pearl does.
Only found in warm, shallow, tropical seas without any terrigenous input (no mountains).

22. Ooids under the Scope
Creamy, chalky white grains that are very well rounded.