Tremolite forms a series with actinolite and ferro-actinolite. Major sources for these forms of actinolite are Taiwan and Canada. Some forms of actinolite are used as gemstones. Another gem variety is the chatoyant form known as "cat's-eye actinolite". Chlorite and to a lesser extent actinolite typically exhibit small, flat or acicular crystal habits. Typical skarn minerals include pyroxene, garnet, idocrase, wollastonite, actinolite, magnetite or hematite, epidote and scapolite. Actinolite and feldspar were also found at Ivy Tor. Much of the asbestos is known to emanate from fibrous tremolite or actinolite. Amosite, crocidolite, tremolite, anthophyllite and actinolite are members of the amphibole class. Greenschists often have some foliation resulting in mineral alignment, especially of chlorite and actinolite. Ferroactinolite is pleochroic and has a higher refractive index and surface relief than actinolite. Less common minerals can include biotite, garnet, actinolite, epidote, chalcedony, prehnite, and wodginite. These are&colon; anthophyllite, riebeckite, cummingtonite/grunerite series, and actinolite/tremolite series. Transparent actinolite is rare and is faceted for gem collectors. Like tremolite, asbestiform actinolite is regulated as asbestos.